Merge pull request #2887 from python-poetry/fix-transitive-extras

Fix and improve handling of extras while resolving dependencies

Merge pull request #2887 from python-poetry/fix-transitive-extras
Fix and improve handling of extras while resolving dependencies
5acf8fa6 · Sébastien Eustace · GitHub · b32051f1 · 55ebb9cd · 5acf8fa6
Commit 5acf8fa6 authored Sep 18, 2020 by Sébastien Eustace Committed by GitHub Sep 18, 2020
59 changed files
--- a/poetry.lock
+++ b/poetry.lock
@@ -461,7 +461,7 @@ six = ">=1.0.0,<2.0.0"
 [[package]]
 name = "more-itertools"
-version = "8.3.0"
+version = "8.4.0"
 description = "More routines for operating on iterables, beyond itertools"
 category = "dev"
 optional = false
@@ -469,7 +469,7 @@ python-versions = ">=3.5"
 [[package]]
 name = "more-itertools"
-version = "8.4.0"
+version = "8.5.0"
 description = "More routines for operating on iterables, beyond itertools"
 category = "dev"
 optional = false
@@ -561,8 +561,8 @@ importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 [[package]]
 name = "poetry-core"
-version = "1.0.0a9"
+version = "1.0.0b1"
-description = "Core utilities for Poetry"
+description = "Poetry PEP 517 Build Backend"
 category = "main"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
@@ -984,7 +984,7 @@ contextlib2 = {version = "*", markers = "python_version < \"3.4\""}
 [metadata]
 lock-version = "1.1"
 python-versions = "~2.7 || ^3.5"
-content-hash = "9528141e0eb24000c6f245065820732b3977d1c7d14c14fbcedf77e91c4a3e68"
+content-hash = "062aef66c1c37dce14fcb2a66841afe97937ce9150136ff8dfa45e43d796821f"
 [metadata.files]
 appdirs = [
@@ -1217,10 +1217,10 @@ more-itertools = [
    {file = "more-itertools-5.0.0.tar.gz", hash = "sha256:38a936c0a6d98a38bcc2d03fdaaedaba9f412879461dd2ceff8d37564d6522e4"},
    {file = "more_itertools-5.0.0-py2-none-any.whl", hash = "sha256:c0a5785b1109a6bd7fac76d6837fd1feca158e54e521ccd2ae8bfe393cc9d4fc"},
    {file = "more_itertools-5.0.0-py3-none-any.whl", hash = "sha256:fe7a7cae1ccb57d33952113ff4fa1bc5f879963600ed74918f1236e212ee50b9"},
-    {file = "more-itertools-8.3.0.tar.gz", hash = "sha256:558bb897a2232f5e4f8e2399089e35aecb746e1f9191b6584a151647e89267be"},
-    {file = "more_itertools-8.3.0-py3-none-any.whl", hash = "sha256:7818f596b1e87be009031c7653d01acc46ed422e6656b394b0f765ce66ed4982"},
    {file = "more-itertools-8.4.0.tar.gz", hash = "sha256:68c70cc7167bdf5c7c9d8f6954a7837089c6a36bf565383919bb595efb8a17e5"},
    {file = "more_itertools-8.4.0-py3-none-any.whl", hash = "sha256:b78134b2063dd214000685165d81c154522c3ee0a1c0d4d113c80361c234c5a2"},
+    {file = "more-itertools-8.5.0.tar.gz", hash = "sha256:6f83822ae94818eae2612063a5101a7311e68ae8002005b5e05f03fd74a86a20"},
+    {file = "more_itertools-8.5.0-py3-none-any.whl", hash = "sha256:9b30f12df9393f0d28af9210ff8efe48d10c94f73e5daf886f10c4b0b0b4f03c"},
 ]
 msgpack = [
    {file = "msgpack-1.0.0-cp35-cp35m-manylinux1_i686.whl", hash = "sha256:cec8bf10981ed70998d98431cd814db0ecf3384e6b113366e7f36af71a0fca08"},
@@ -1270,8 +1270,8 @@ pluggy = [
    {file = "pluggy-0.13.1.tar.gz", hash = "sha256:15b2acde666561e1298d71b523007ed7364de07029219b604cf808bfa1c765b0"},
 ]
 poetry-core = [
-    {file = "poetry-core-1.0.0a9.tar.gz", hash = "sha256:f08e9829fd06609ca5615faa91739b589eb71e025a6aaf7ddffb698676eb7c8c"},
+    {file = "poetry-core-1.0.0b1.tar.gz", hash = "sha256:c7a64770780f6a4998eee1e260fc3b7e22fa1c9b94b05c0faa13aa512f95eaa1"},
-    {file = "poetry_core-1.0.0a9-py2.py3-none-any.whl", hash = "sha256:79a63629ae44533ba9aa828e0eff0002c61b3af5fc9bec212e006cc643f4eb19"},
+    {file = "poetry_core-1.0.0b1-py2.py3-none-any.whl", hash = "sha256:92d2a33c27c733e746425c6506fdf583909e3ce5de4591deb23a4efb13f1a72c"},
 ]
 pre-commit = [
    {file = "pre_commit-2.6.0-py2.py3-none-any.whl", hash = "sha256:e8b1315c585052e729ab7e99dcca5698266bedce9067d21dc909c23e3ceed626"},
@@ -1371,6 +1371,7 @@ six = [
 ]
 subprocess32 = [
    {file = "subprocess32-3.5.4-cp27-cp27m-macosx_10_6_intel.whl", hash = "sha256:88e37c1aac5388df41cc8a8456bb49ebffd321a3ad4d70358e3518176de3a56b"},
+    {file = "subprocess32-3.5.4-cp27-cp27mu-manylinux2014_x86_64.whl", hash = "sha256:e45d985aef903c5b7444d34350b05da91a9e0ea015415ab45a21212786c649d0"},
    {file = "subprocess32-3.5.4.tar.gz", hash = "sha256:eb2937c80497978d181efa1b839ec2d9622cf9600a039a79d0e108d1f9aec79d"},
 ]
 termcolor = [

--- a/poetry/console/commands/debug/resolve.py
+++ b/poetry/console/commands/debug/resolve.py
@@ -29,6 +29,7 @@ class DebugResolveCommand(InitCommand):
    def handle(self):
        from poetry.core.packages.project_package import ProjectPackage
+        from poetry.factory import Factory
        from poetry.io.null_io import NullIO
        from poetry.puzzle import Solver
        from poetry.repositories.pool import Pool
@@ -59,7 +60,6 @@ class DebugResolveCommand(InitCommand):
            for constraint in requirements:
                name = constraint.pop("name")
-                dep = package.add_dependency(name, constraint)
                extras = []
                for extra in self.option("extras"):
                    if " " in extra:
@@ -67,8 +67,9 @@ class DebugResolveCommand(InitCommand):
                    else:
                        extras.append(extra)
-                for ex in extras:
+                constraint["extras"] = extras
-                    dep.extras.append(ex)
+                package.add_dependency(Factory.create_dependency(name, constraint))
        package.python_versions = self.option("python") or (
            self.poetry.package.python_versions
@@ -122,7 +123,7 @@ class DebugResolveCommand(InitCommand):
            pkg = op.package
            row = [
-                "<c1>{}</c1>".format(pkg.name),
+                "<c1>{}</c1>".format(pkg.complete_name),
                "<b>{}</b>".format(pkg.version),
                "",
            ]

--- a/poetry/console/commands/init.py
+++ b/poetry/console/commands/init.py
@@ -388,7 +388,7 @@ The <c1>init</c1> command creates a basic <comment>pyproject.toml</> file in the
                        pair["extras"] = extras
                    package = Provider.get_package_from_vcs(
-                        "git", url.url, reference=pair.get("rev")
+                        "git", url.url, rev=pair.get("rev")
                    )
                    pair["name"] = package.name
                    result.append(pair)

--- a/poetry/console/commands/show.py
+++ b/poetry/console/commands/show.py
@@ -37,6 +37,7 @@ lists all packages available."""
        from poetry.core.semver import Version
        from poetry.repositories.installed_repository import InstalledRepository
+        from poetry.utils.helpers import get_package_version_display_string
        package = self.argument("package")
@@ -144,12 +145,31 @@ lists all packages available."""
                if not self.option("outdated") or update_status != "up-to-date":
                    name_length = max(name_length, current_length)
                    version_length = max(
-                        version_length, len(locked.full_pretty_version)
+                        version_length,
+                        len(
+                            get_package_version_display_string(
+                                locked, root=self.poetry.file.parent
+                            )
+                        ),
+                    )
+                    latest_length = max(
+                        latest_length,
+                        len(
+                            get_package_version_display_string(
+                                latest, root=self.poetry.file.parent
+                            )
+                        ),
                    )
-                    latest_length = max(latest_length, len(latest.full_pretty_version))
            else:
                name_length = max(name_length, current_length)
-                version_length = max(version_length, len(locked.full_pretty_version))
+                version_length = max(
+                    version_length,
+                    len(
+                        get_package_version_display_string(
+                            locked, root=self.poetry.file.parent
+                        )
+                    ),
+                )
        write_version = name_length + version_length + 3 <= width
        write_latest = name_length + version_length + latest_length + 3 <= width
@@ -185,7 +205,10 @@ lists all packages available."""
            )
            if write_version:
                line += " <b>{:{}}</b>".format(
-                    locked.full_pretty_version, version_length
+                    get_package_version_display_string(
+                        locked, root=self.poetry.file.parent
+                    ),
+                    version_length,
                )
            if show_latest:
                latest = latest_packages[locked.pretty_name]
@@ -199,7 +222,11 @@ lists all packages available."""
                        color = "yellow"
                    line += " <fg={}>{:{}}</>".format(
-                        color, latest.full_pretty_version, latest_length
+                        color,
+                        get_package_version_display_string(
+                            latest, root=self.poetry.file.parent
+                        ),
+                        latest_length,
                    )
            if write_description:

--- a/poetry/factory.py
+++ b/poetry/factory.py
--- a/poetry/inspection/info.py
+++ b/poetry/inspection/info.py
@@ -69,6 +69,9 @@ class PackageInfo:
        self.requires_python = requires_python
        self.files = files or []
        self._cache_version = cache_version
+        self._source_type = None
+        self._source_url = None
+        self._source_reference = None
    @property
    def cache_version(self):  # type: () -> Optional[str]
@@ -136,7 +139,13 @@ class PackageInfo:
                "Unable to retrieve the package version for {}".format(name)
            )
-        package = Package(name=name, version=self.version)
+        package = Package(
+            name=name,
+            version=self.version,
+            source_type=self._source_type,
+            source_url=self._source_url,
+            source_reference=self._source_reference,
+        )
        package.description = self.summary
        package.root_dir = root_dir
        package.python_versions = self.requires_python or "*"
@@ -166,14 +175,9 @@ class PackageInfo:
                        # this is the first time we encounter this extra for this package
                        package.extras[extra] = []
-                    # Activate extra dependencies if specified
-                    if extras and extra in extras:
-                        dependency.activate()
                    package.extras[extra].append(dependency)
-            if not dependency.is_optional() or dependency.is_activated():
+            if dependency not in package.requires:
-                # we skip add only if the dependency is option and was not activated as part of an extra
                package.requires.append(dependency)
        return package
@@ -197,7 +201,7 @@ class PackageInfo:
                with requires.open(encoding="utf-8") as f:
                    requirements = parse_requires(f.read())
-        return cls(
+        info = cls(
            name=dist.name,
            version=dist.version,
            summary=dist.summary,
@@ -206,6 +210,11 @@ class PackageInfo:
            requires_python=dist.requires_python,
        )
+        info._source_type = "file"
+        info._source_url = Path(dist.filename).resolve().as_posix()
+        return info
    @classmethod
    def _from_sdist_file(cls, path):  # type: (Path) -> PackageInfo
        """
@@ -501,23 +510,26 @@ class PackageInfo:
        """
        project_package = cls._get_poetry_package(path)
        if project_package:
-            return cls.from_package(project_package)
+            info = cls.from_package(project_package)
+        else:
+            info = cls.from_metadata(path)
-        info = cls.from_metadata(path)
+            if not info or info.requires_dist is None:
+                try:
+                    if disable_build:
+                        info = cls.from_setup_files(path)
+                    else:
+                        info = cls._pep517_metadata(path)
+                except PackageInfoError:
+                    if not info:
+                        raise
-        if info and info.requires_dist is not None:
+                    # we discovered PkgInfo but no requirements were listed
-            # return only if requirements are discovered
-            return info
-        try:
+        info._source_type = "directory"
-            if disable_build:
+        info._source_url = path.as_posix()
-                return cls.from_setup_files(path)
-            return cls._pep517_metadata(path)
+        return info
-        except PackageInfoError as e:
-            if info:
-                # we discovered PkgInfo but no requirements were listed
-                return info
-            raise e
    @classmethod
    def from_sdist(cls, path):  # type: (Path) -> PackageInfo

--- a/poetry/installation/executor.py
+++ b/poetry/installation/executor.py
@@ -556,7 +556,7 @@ class Executor(object):
        git.checkout(package.source_reference, src_dir)
        # Now we just need to install from the source directory
-        package.source_url = str(src_dir)
+        package._source_url = str(src_dir)
        return self._install_directory(operation)
@@ -599,7 +599,7 @@ class Executor(object):
    def _download_archive(self, operation, link):  # type: (Operation, Link) -> Path
        response = self._authenticator.request(
-            "get", link.url, stream=True, io=self._sections.get(id(operation))
+            "get", link.url, stream=True, io=self._sections.get(id(operation), self._io)
        )
        wheel_size = response.headers.get("content-length")
        operation_message = self.get_operation_message(operation)

--- a/poetry/installation/pip_installer.py
+++ b/poetry/installation/pip_installer.py
@@ -261,8 +261,8 @@ class PipInstaller(BaseInstaller):
        # Now we just need to install from the source directory
        pkg = Package(package.name, package.version)
-        pkg.source_type = "directory"
+        pkg._source_type = "directory"
-        pkg.source_url = str(src_dir)
+        pkg._source_url = str(src_dir)
        pkg.develop = package.develop
        self.install_directory(pkg)
--- a/poetry/mixology/incompatibility.py
+++ b/poetry/mixology/incompatibility.py
@@ -36,18 +36,18 @@ class Incompatibility:
            # Short-circuit in the common case of a two-term incompatibility with
            # two different packages (for example, a dependency).
            or len(terms) == 2
-            and terms[0].dependency.name != terms[-1].dependency.name
+            and terms[0].dependency.complete_name != terms[-1].dependency.complete_name
        ):
            pass
        else:
            # Coalesce multiple terms about the same package if possible.
            by_name = {}  # type: Dict[str, Dict[str, Term]]
            for term in terms:
-                if term.dependency.name not in by_name:
+                if term.dependency.complete_name not in by_name:
-                    by_name[term.dependency.name] = {}
+                    by_name[term.dependency.complete_name] = {}
-                by_ref = by_name[term.dependency.name]
+                by_ref = by_name[term.dependency.complete_name]
-                ref = term.dependency.name
+                ref = term.dependency.complete_name
                if ref in by_ref:
                    by_ref[ref] = by_ref[ref].intersect(term)
@@ -432,7 +432,7 @@ class Incompatibility:
    def _terse(self, term, allow_every=False):
        if allow_every and term.constraint.is_any():
-            return "every version of {}".format(term.dependency.name)
+            return "every version of {}".format(term.dependency.complete_name)
        return str(term.dependency)

--- a/poetry/mixology/partial_solution.py
+++ b/poetry/mixology/partial_solution.py
@@ -65,7 +65,7 @@ class PartialSolution:
        return [
            term.dependency
            for term in self._positive.values()
-            if term.dependency.name not in self._decisions
+            if term.dependency.complete_name not in self._decisions
        ]
    def decide(self, package):  # type: (Package) -> None
@@ -81,7 +81,7 @@ class PartialSolution:
            self._attempted_solutions += 1
        self._backtracking = False
-        self._decisions[package.name] = package
+        self._decisions[package.complete_name] = package
        self._assign(
            Assignment.decision(package, self.decision_level, len(self._assignments))
@@ -120,9 +120,9 @@ class PartialSolution:
        packages = set()
        while self._assignments[-1].decision_level > decision_level:
            removed = self._assignments.pop(-1)
-            packages.add(removed.dependency.name)
+            packages.add(removed.dependency.complete_name)
            if removed.is_decision():
-                del self._decisions[removed.dependency.name]
+                del self._decisions[removed.dependency.complete_name]
        # Re-compute _positive and _negative for the packages that were removed.
        for package in packages:
@@ -133,21 +133,21 @@ class PartialSolution:
                del self._negative[package]
        for assignment in self._assignments:
-            if assignment.dependency.name in packages:
+            if assignment.dependency.complete_name in packages:
                self._register(assignment)
    def _register(self, assignment):  # type: (Assignment) -> None
        """
        Registers an Assignment in _positive or _negative.
        """
-        name = assignment.dependency.name
+        name = assignment.dependency.complete_name
        old_positive = self._positive.get(name)
        if old_positive is not None:
            self._positive[name] = old_positive.intersect(assignment)
            return
-        ref = assignment.dependency.name
+        ref = assignment.dependency.complete_name
        negative_by_ref = self._negative.get(name)
        old_negative = None if negative_by_ref is None else negative_by_ref.get(ref)
        if old_negative is None:
@@ -174,12 +174,12 @@ class PartialSolution:
        assigned_term = None  # type: Term
        for assignment in self._assignments:
-            if assignment.dependency.name != term.dependency.name:
+            if assignment.dependency.complete_name != term.dependency.complete_name:
                continue
            if (
                not assignment.dependency.is_root
-                and not assignment.dependency.name == term.dependency.name
+                and not assignment.dependency.is_same_package_as(term.dependency)
            ):
                if not assignment.is_positive():
                    continue
@@ -203,15 +203,15 @@ class PartialSolution:
        return self.relation(term) == SetRelation.SUBSET
    def relation(self, term):  # type: (Term) -> int
-        positive = self._positive.get(term.dependency.name)
+        positive = self._positive.get(term.dependency.complete_name)
        if positive is not None:
            return positive.relation(term)
-        by_ref = self._negative.get(term.dependency.name)
+        by_ref = self._negative.get(term.dependency.complete_name)
        if by_ref is None:
            return SetRelation.OVERLAPPING
-        negative = by_ref[term.dependency.name]
+        negative = by_ref[term.dependency.complete_name]
        if negative is None:
            return SetRelation.OVERLAPPING

--- a/poetry/mixology/term.py
+++ b/poetry/mixology/term.py
@@ -38,7 +38,7 @@ class Term(object):
        Returns whether this term satisfies another.
        """
        return (
-            self.dependency.name == other.dependency.name
+            self.dependency.complete_name == other.dependency.complete_name
            and self.relation(other) == SetRelation.SUBSET
        )
@@ -47,9 +47,9 @@ class Term(object):
        Returns the relationship between the package versions
        allowed by this term and another.
        """
-        if self.dependency.name != other.dependency.name:
+        if self.dependency.complete_name != other.dependency.complete_name:
            raise ValueError(
-                "{} should refer to {}".format(other, self.dependency.name)
+                "{} should refer to {}".format(other, self.dependency.complete_name)
            )
        other_constraint = other.constraint
@@ -111,9 +111,9 @@ class Term(object):
        Returns a Term that represents the packages
        allowed by both this term and another
        """
-        if self.dependency.name != other.dependency.name:
+        if self.dependency.complete_name != other.dependency.complete_name:
            raise ValueError(
-                "{} should refer to {}".format(other, self.dependency.name)
+                "{} should refer to {}".format(other, self.dependency.complete_name)
            )
        if self._compatible_dependency(other.dependency):
@@ -151,17 +151,14 @@ class Term(object):
        return (
            self.dependency.is_root
            or other.is_root
-            or other.name == self.dependency.name
+            or other.is_same_package_as(self.dependency)
        )
    def _non_empty_term(self, constraint, is_positive):
        if constraint.is_empty():
            return
-        dep = Dependency(self.dependency.name, constraint)
+        return Term(self.dependency.with_constraint(constraint), is_positive)
-        dep.python_versions = str(self.dependency.python_versions)
-        return Term(dep, is_positive)
    def __str__(self):
        return "{}{}".format("not " if not self.is_positive() else "", self._dependency)

--- a/poetry/mixology/version_solver.py
+++ b/poetry/mixology/version_solver.py
@@ -183,7 +183,7 @@ class VersionSolver:
            unsatisfied.dependency, not unsatisfied.is_positive(), incompatibility
        )
-        return unsatisfied.dependency.name
+        return unsatisfied.dependency.complete_name
    def _resolve_conflict(
        self, incompatibility
@@ -371,7 +371,7 @@ class VersionSolver:
                self._add_incompatibility(
                    Incompatibility([Term(dependency, True)], PackageNotFoundCause(e))
                )
-                return dependency.name
+                return dependency.complete_name
            try:
                version = packages[0]
@@ -387,7 +387,7 @@ class VersionSolver:
                Incompatibility([Term(dependency, True)], NoVersionsCause())
            )
-            return dependency.name
+            return dependency.complete_name
        version = self._provider.complete_package(version)
@@ -402,7 +402,7 @@ class VersionSolver:
            # unit propagation which will guide us to choose a better version.
            conflict = conflict or all(
                [
-                    term.dependency.name == dependency.name
+                    term.dependency.complete_name == dependency.complete_name
                    or self._solution.satisfies(term)
                    for term in incompatibility.terms
                ]
@@ -411,10 +411,12 @@ class VersionSolver:
        if not conflict:
            self._solution.decide(version)
            self._log(
-                "selecting {} ({})".format(version.name, version.full_pretty_version)
+                "selecting {} ({})".format(
+                    version.complete_name, version.full_pretty_version
+                )
            )
-        return dependency.name
+        return dependency.complete_name
    def _excludes_single_version(self, constraint):  # type: (Any) -> bool
        return isinstance(VersionRange().difference(constraint), Version)
@@ -435,31 +437,29 @@ class VersionSolver:
        self._log("fact: {}".format(incompatibility))
        for term in incompatibility.terms:
-            if term.dependency.name not in self._incompatibilities:
+            if term.dependency.complete_name not in self._incompatibilities:
-                self._incompatibilities[term.dependency.name] = []
+                self._incompatibilities[term.dependency.complete_name] = []
-            if incompatibility in self._incompatibilities[term.dependency.name]:
+            if (
+                incompatibility
+                in self._incompatibilities[term.dependency.complete_name]
+            ):
                continue
-            self._incompatibilities[term.dependency.name].append(incompatibility)
+            self._incompatibilities[term.dependency.complete_name].append(
+                incompatibility
+            )
    def _get_locked(self, dependency):  # type: (Dependency) -> Union[Package, None]
-        if dependency.name in self._use_latest:
+        if dependency.complete_name in self._use_latest:
            return
-        locked = self._locked.get(dependency.name)
+        locked = self._locked.get(dependency.complete_name)
        if not locked:
            return
-        if dependency.extras:
+        if not dependency.is_same_package_as(locked):
-            locked.requires_extras = dependency.extras
+            return
-        if not dependency.transitive_marker.without_extras().is_any():
-            marker_intersection = dependency.transitive_marker.without_extras().intersect(
-                locked.dependency.marker.without_extras()
-            )
-            if not marker_intersection.is_empty():
-                locked.dependency.transitive_marker = marker_intersection
        return locked

--- a/poetry/packages/dependency_package.py
+++ b/poetry/packages/dependency_package.py
+from typing import List
+from poetry.core.packages.dependency import Dependency
+from poetry.core.packages.package import Package
 class DependencyPackage(object):
-    def __init__(self, dependency, package):
+    def __init__(self, dependency, package):  # type: (Dependency, Package) -> None
        self._dependency = dependency
        self._package = package
    @property
-    def dependency(self):
+    def dependency(self):  # type: () -> Dependency
        return self._dependency
    @property
-    def package(self):
+    def package(self):  # type: () -> Package
        return self._package
    def clone(self):  # type: () -> DependencyPackage
        return self.__class__(self._dependency, self._package.clone())
+    def with_features(self, features):  # type: (List[str]) -> "DependencyPackage"
+        return self.__class__(self._dependency, self._package.with_features(features))
+    def without_features(self):  # type: () -> "DependencyPackage"
+        return self.with_features([])
    def __getattr__(self, name):
        return getattr(self._package, name)

--- a/poetry/packages/locker.py
+++ b/poetry/packages/locker.py
 import json
 import logging
+import os
 import re
 from hashlib import sha256
 from typing import List
+from tomlkit import array
 from tomlkit import document
 from tomlkit import inline_table
 from tomlkit import item
@@ -18,6 +20,7 @@ from poetry.core.packages.package import Package
 from poetry.core.semver import parse_constraint
 from poetry.core.semver.version import Version
 from poetry.core.version.markers import parse_marker
+from poetry.utils._compat import OrderedDict
 from poetry.utils._compat import Path
 from poetry.utils.toml_file import TomlFile
@@ -75,6 +78,8 @@ class Locker(object):
        """
        Searches and returns a repository of locked packages.
        """
+        from poetry.factory import Factory
        if not self.is_locked():
            return poetry.repositories.Repository()
@@ -92,7 +97,21 @@ class Locker(object):
            return packages
        for info in locked_packages:
-            package = Package(info["name"], info["version"], info["version"])
+            source = info.get("source", {})
+            source_type = source.get("type")
+            url = source.get("url")
+            if source_type in ["directory", "file"]:
+                url = self._lock.path.parent.joinpath(url).resolve().as_posix()
+            package = Package(
+                info["name"],
+                info["version"],
+                info["version"],
+                source_type=source_type,
+                source_url=url,
+                source_reference=source.get("reference"),
+                source_resolved_reference=source.get("resolved_reference"),
+            )
            package.description = info.get("description", "")
            package.category = info["category"]
            package.optional = info["optional"]
@@ -137,20 +156,23 @@ class Locker(object):
            for dep_name, constraint in info.get("dependencies", {}).items():
                if isinstance(constraint, list):
                    for c in constraint:
-                        package.add_dependency(dep_name, c)
+                        package.add_dependency(
+                            Factory.create_dependency(
+                                dep_name, c, root_dir=self._lock.path.parent
+                            )
+                        )
                    continue
-                package.add_dependency(dep_name, constraint)
+                package.add_dependency(
+                    Factory.create_dependency(
+                        dep_name, constraint, root_dir=self._lock.path.parent
+                    )
+                )
            if "develop" in info:
                package.develop = info["develop"]
-            if "source" in info:
-                package.source_type = info["source"].get("type", "")
-                package.source_url = info["source"]["url"]
-                package.source_reference = info["source"]["reference"]
            packages.add_package(package)
        return packages
@@ -181,15 +203,17 @@ class Locker(object):
        if root.extras:
            lock["extras"] = {
                extra: [dep.pretty_name for dep in deps]
-                for extra, deps in root.extras.items()
+                for extra, deps in sorted(root.extras.items())
            }
-        lock["metadata"] = {
+        lock["metadata"] = OrderedDict(
-            "lock-version": self._VERSION,
+            [
-            "python-versions": root.python_versions,
+                ("lock-version", self._VERSION),
-            "content-hash": self._content_hash,
+                ("python-versions", root.python_versions),
-            "files": files,
+                ("content-hash", self._content_hash),
-        }
+                ("files", files),
+            ]
+        )
        if not self.is_locked() or lock != self.lock_data:
            self._write_lock_data(lock)
@@ -270,9 +294,6 @@ class Locker(object):
    def _dump_package(self, package):  # type: (Package) -> dict
        dependencies = {}
        for dependency in sorted(package.requires, key=lambda d: d.name):
-            if dependency.is_optional() and not dependency.is_activated():
-                continue
            if dependency.pretty_name not in dependencies:
                dependencies[dependency.pretty_name] = []
@@ -298,15 +319,27 @@ class Locker(object):
                    constraint["version"] for constraint in constraints
                ]
-        data = {
+        data = OrderedDict(
-            "name": package.pretty_name,
+            [
-            "version": package.pretty_version,
+                ("name", package.pretty_name),
-            "description": package.description or "",
+                ("version", package.pretty_version),
-            "category": package.category,
+                ("description", package.description or ""),
-            "optional": package.optional,
+                ("category", package.category),
-            "python-versions": package.python_versions,
+                ("optional", package.optional),
-            "files": sorted(package.files, key=lambda x: x["file"]),
+                ("python-versions", package.python_versions),
-        }
+                ("files", sorted(package.files, key=lambda x: x["file"])),
+            ]
+        )
+        if dependencies:
+            data["dependencies"] = table()
+            for k, constraints in dependencies.items():
+                if len(constraints) == 1:
+                    data["dependencies"][k] = constraints[0]
+                else:
+                    data["dependencies"][k] = array().multiline(True)
+                    for constraint in constraints:
+                        data["dependencies"][k].append(constraint)
        if package.extras:
            extras = {}
@@ -318,20 +351,29 @@ class Locker(object):
            data["extras"] = extras
-        if dependencies:
+        if package.source_url:
-            for k, constraints in dependencies.items():
+            url = package.source_url
-                if len(constraints) == 1:
+            if package.source_type in ["file", "directory"]:
-                    dependencies[k] = constraints[0]
+                # The lock file should only store paths relative to the root project
+                url = Path(
+                    os.path.relpath(
+                        Path(url).as_posix(), self._lock.path.parent.as_posix()
+                    )
+                ).as_posix()
-            data["dependencies"] = dependencies
+            data["source"] = OrderedDict()
-        if package.source_url:
-            data["source"] = {
-                "url": package.source_url,
-                "reference": package.source_reference,
-            }
            if package.source_type:
                data["source"]["type"] = package.source_type
+            data["source"]["url"] = url
+            if package.source_reference:
+                data["source"]["reference"] = package.source_reference
+            if package.source_resolved_reference:
+                data["source"]["resolved_reference"] = package.source_resolved_reference
            if package.source_type == "directory":
                data["develop"] = package.develop

--- a/poetry/packages/package_collection.py
+++ b/poetry/packages/package_collection.py
@@ -14,7 +14,9 @@ class PackageCollection(list):
            self.append(package)
    def append(self, package):
-        if not isinstance(package, DependencyPackage):
+        if isinstance(package, DependencyPackage):
-            package = DependencyPackage(self._dependency, package)
+            package = package.package
+        package = DependencyPackage(self._dependency, package)
        return super(PackageCollection, self).append(package)
--- a/poetry/puzzle/provider.py
+++ b/poetry/puzzle/provider.py
@@ -103,7 +103,7 @@ class Provider:
        for constraint in self._search_for.keys():
            if (
-                constraint.name == dependency.name
+                constraint.is_same_package_as(dependency)
                and constraint.constraint.intersect(dependency.constraint)
                == dependency.constraint
            ):
@@ -132,15 +132,7 @@ class Provider:
        elif dependency.is_url():
            packages = self.search_for_url(dependency)
        else:
-            constraint = dependency.constraint
+            packages = self._pool.find_packages(dependency)
-            packages = self._pool.find_packages(
-                dependency.name,
-                constraint,
-                extras=dependency.extras,
-                allow_prereleases=dependency.allows_prereleases(),
-                repository=dependency.source_name,
-            )
            packages.sort(
                key=lambda p: (
@@ -167,17 +159,12 @@ class Provider:
        package = self.get_package_from_vcs(
            dependency.vcs,
            dependency.source,
-            dependency.reference,
+            branch=dependency.branch,
+            tag=dependency.tag,
+            rev=dependency.rev,
            name=dependency.name,
        )
-        for extra in dependency.extras:
-            if extra in package.extras:
-                for dep in package.extras[extra]:
-                    dep.activate()
-                package.requires += package.extras[extra]
        dependency._constraint = package.version
        dependency._pretty_constraint = package.version.text
@@ -187,7 +174,7 @@ class Provider:
    @classmethod
    def get_package_from_vcs(
-        cls, vcs, url, reference=None, name=None
+        cls, vcs, url, branch=None, tag=None, rev=None, name=None
    ):  # type: (str, str, Optional[str], Optional[str]) -> Package
        if vcs != "git":
            raise ValueError("Unsupported VCS dependency {}".format(vcs))
@@ -199,6 +186,7 @@ class Provider:
        try:
            git = Git()
            git.clone(url, tmp_dir)
+            reference = branch or tag or rev
            if reference is not None:
                git.checkout(reference, tmp_dir)
            else:
@@ -207,10 +195,10 @@ class Provider:
            revision = git.rev_parse(reference, tmp_dir).strip()
            package = cls.get_package_from_directory(tmp_dir, name=name)
+            package._source_type = "git"
-            package.source_type = "git"
+            package._source_url = url
-            package.source_url = url
+            package._source_reference = reference
-            package.source_reference = revision
+            package._source_resolved_reference = revision
        except Exception:
            raise
        finally:
@@ -242,18 +230,10 @@ class Provider:
        if dependency.base is not None:
            package.root_dir = dependency.base
-        package.source_url = dependency.path.as_posix()
        package.files = [
            {"file": dependency.path.name, "hash": "sha256:" + dependency.hash()}
        ]
-        for extra in dependency.extras:
-            if extra in package.extras:
-                for dep in package.extras[extra]:
-                    dep.activate()
-                package.requires += package.extras[extra]
        return [package]
    @classmethod
@@ -267,9 +247,6 @@ class Provider:
                "Unable to determine package info from path: {}".format(file_path)
            )
-        package.source_type = "file"
-        package.source_url = file_path.as_posix()
        return package
    def search_for_directory(
@@ -289,19 +266,11 @@ class Provider:
            self._deferred_cache[dependency] = (dependency, package)
-        package.source_url = dependency.path.as_posix()
        package.develop = dependency.develop
        if dependency.base is not None:
            package.root_dir = dependency.base
-        for extra in dependency.extras:
-            if extra in package.extras:
-                for dep in package.extras[extra]:
-                    dep.activate()
-                package.requires += package.extras[extra]
        return [package]
    @classmethod
@@ -320,9 +289,6 @@ class Provider:
                )
            )
-        package.source_type = "directory"
-        package.source_url = directory.as_posix()
        return package
    def search_for_url(self, dependency):  # type: (URLDependency) -> List[Package]
@@ -362,8 +328,8 @@ class Provider:
            package = cls.get_package_from_file(temp_dir / file_name)
-        package.source_type = "url"
+        package._source_type = "url"
-        package.source_url = url
+        package._source_url = url
        return package
@@ -447,6 +413,7 @@ class Provider:
    def complete_package(
        self, package
    ):  # type: (DependencyPackage) -> DependencyPackage
        if package.is_root():
            package = package.clone()
            requires = package.all_requires
@@ -461,7 +428,7 @@ class Provider:
                self._pool.package(
                    package.name,
                    package.version.text,
-                    extras=package.requires_extras,
+                    extras=package.dependency.extras,
                    repository=package.dependency.source_name,
                ),
            )
@@ -480,13 +447,44 @@ class Provider:
            elif r.is_url():
                self.search_for_url(r)
-        _dependencies = [
+        optional_dependencies = []
-            r
+        activated_extras = []
-            for r in requires
+        for extra in package.dependency.extras:
-            if self._python_constraint.allows_any(r.python_constraint)
+            if extra not in package.extras:
-            and r.name not in self.UNSAFE_PACKAGES
+                continue
-            and (not self._env or r.marker.validate(self._env.marker_env))
-        ]
+            activated_extras.append(extra)
+            optional_dependencies += [d.name for d in package.extras[extra]]
+        _dependencies = []
+        # If some extras/features were required, we need to
+        # add a special dependency representing the base package
+        # to the current package
+        if package.dependency.extras:
+            if activated_extras:
+                package = package.with_features(activated_extras)
+            _dependencies.append(package.without_features().to_dependency())
+        for dep in requires:
+            if not self._python_constraint.allows_any(dep.python_constraint):
+                continue
+            if dep.name in self.UNSAFE_PACKAGES:
+                continue
+            if self._env and not dep.marker.validate(self._env.marker_env):
+                continue
+            if (
+                dep.is_optional()
+                and dep.name not in optional_dependencies
+                and not package.is_root()
+            ):
+                continue
+            _dependencies.append(dep)
        overrides = self._overrides.get(package, {})
        dependencies = []
@@ -683,18 +681,6 @@ class Provider:
                    continue
                dep.transitive_python_versions = str(python_constraint_intersection)
-            if (package.dependency.is_directory() or package.dependency.is_file()) and (
-                dep.is_directory() or dep.is_file()
-            ):
-                relative_path = Path(
-                    os.path.relpath(
-                        dep.full_path.as_posix(), package.root_dir.as_posix()
-                    )
-                )
-                # TODO: Improve the way we set the correct relative path for dependencies
-                dep._path = relative_path
            clean_dependencies.append(dep)
        package.requires = clean_dependencies

--- a/poetry/puzzle/solver.py
+++ b/poetry/puzzle/solver.py
@@ -34,7 +34,7 @@ class Solver:
        installed,  # type: Repository
        locked,  # type: Repository
        io,  # type: ConsoleIO
-        remove_untracked=False,  # type: bool,
+        remove_untracked=False,  # type: bool
        provider=None,  # type: Optional[Provider]
    ):
        self._package = package
@@ -100,18 +100,37 @@ class Solver:
                                and locked.source_type == pkg.source_type
                                and locked_source_url == pkg_source_url
                                and locked.source_reference == pkg.source_reference
+                                and locked.source_resolved_reference
+                                == pkg.source_resolved_reference
                            ):
-                                pkg = Package(pkg.name, locked.version)
+                                pkg = Package(
-                                pkg.source_type = "git"
+                                    pkg.name,
-                                pkg.source_url = locked.source_url
+                                    locked.version,
-                                pkg.source_reference = locked.source_reference
+                                    source_type="git",
+                                    source_url=locked.source_url,
+                                    source_reference=locked.source_reference,
+                                    source_resolved_reference=locked.source_resolved_reference,
+                                )
                                break
                        if pkg_source_url != package_source_url or (
-                            pkg.source_reference != package.source_reference
+                            (
+                                not pkg.source_resolved_reference
+                                or not package.source_resolved_reference
+                            )
+                            and pkg.source_reference != package.source_reference
                            and not pkg.source_reference.startswith(
                                package.source_reference
                            )
+                            or (
+                                pkg.source_resolved_reference
+                                and package.source_resolved_reference
+                                and pkg.source_resolved_reference
+                                != package.source_resolved_reference
+                                and not pkg.source_resolved_reference.startswith(
+                                    package.source_resolved_reference
+                                )
+                            )
                        ):
                            operations.append(Update(pkg, package, priority=depths[i]))
                        else:
@@ -226,17 +245,39 @@ class Solver:
                PackageNode(self._package, packages), aggregate_package_nodes
            )
        )
-        # Return the packages in their original order with associated depths
-        final_packages = packages
-        depths = [results[package] for package in packages]
+        # Merging feature packages with base packages
+        final_packages = []
+        depths = []
+        for package in packages:
+            if package.features:
+                for _package in packages:
+                    if (
+                        _package.name == package.name
+                        and not _package.is_same_package_as(package)
+                        and _package.version == package.version
+                    ):
+                        for dep in package.requires:
+                            if dep.is_same_package_as(_package):
+                                continue
+                            if dep not in _package.requires:
+                                _package.requires.append(dep)
+                continue
+            final_packages.append(package)
+            depths.append(results[package])
+        # Return the packages in their original order with associated depths
        return final_packages, depths
 class DFSNode(object):
-    def __init__(self, id, name):
+    def __init__(self, id, name, base_name):
        self.id = id
        self.name = name
+        self.base_name = base_name
    def reachable(self):
        return []
@@ -302,13 +343,7 @@ def dfs_visit(node, back_edges, visited, sorted_nodes):
 class PackageNode(DFSNode):
    def __init__(
-        self,
+        self, package, packages, previous=None, previous_dep=None, dep=None,
-        package,
-        packages,
-        previous=None,
-        previous_dep=None,
-        dep=None,
-        is_activated=True,
    ):
        self.package = package
        self.packages = packages
@@ -323,11 +358,12 @@ class PackageNode(DFSNode):
            self.optional = True
        else:
            self.category = dep.category
-            self.optional = dep.is_optional() and not dep.is_activated()
+            self.optional = dep.is_optional()
-        if not is_activated:
-            self.optional = True
        super(PackageNode, self).__init__(
-            (package.name, self.category, self.optional), package.name
+            (package.complete_name, self.category, self.optional),
+            package.complete_name,
+            package.name,
        )
    def reachable(self):
@@ -341,29 +377,7 @@ class PackageNode(DFSNode):
            return []
        for dependency in self.package.all_requires:
-            is_activated = True
+            if self.previous and self.previous.name == dependency.name:
-            if dependency.is_optional():
-                if not self.package.is_root() and (
-                    not self.previous_dep or not self.previous_dep.extras
-                ):
-                    continue
-                is_activated = False
-                for group, extra_deps in self.package.extras.items():
-                    if self.dep:
-                        extras = self.previous_dep.extras
-                    elif self.package.is_root():
-                        extras = self.package.extras
-                    else:
-                        extras = []
-                    if group in extras and dependency.name in (
-                        d.name for d in self.package.extras[group]
-                    ):
-                        is_activated = True
-                        break
-            if self.previous and self.previous.package.name == dependency.name:
                # We have a circular dependency.
                # Since the dependencies are resolved we can
                # simply skip it because we already have it
@@ -372,8 +386,9 @@ class PackageNode(DFSNode):
                continue
            for pkg in self.packages:
-                if pkg.name == dependency.name and dependency.constraint.allows(
+                if (
-                    pkg.version
+                    pkg.complete_name == dependency.complete_name
+                    and dependency.constraint.allows(pkg.version)
                ):
                    # If there is already a child with this name
                    # we merge the requirements
@@ -383,6 +398,7 @@ class PackageNode(DFSNode):
                        for child in children
                    ):
                        continue
                    children.append(
                        PackageNode(
                            pkg,
@@ -390,15 +406,21 @@ class PackageNode(DFSNode):
                            self,
                            dependency,
                            self.dep or dependency,
-                            is_activated=is_activated,
                        )
                    )
        return children
    def visit(self, parents):
        # The root package, which has no parents, is defined as having depth -1
        # So that the root package's top-level dependencies have depth 0.
-        self.depth = 1 + max([parent.depth for parent in parents] + [-2])
+        self.depth = 1 + max(
+            [
+                parent.depth if parent.base_name != self.base_name else parent.depth - 1
+                for parent in parents
+            ]
+            + [-2]
+        )
 def aggregate_package_nodes(nodes, children):

--- a/poetry/repositories/base_repository.py
+++ b/poetry/repositories/base_repository.py
@@ -12,9 +12,7 @@ class BaseRepository(object):
    def package(self, name, version, extras=None):
        raise NotImplementedError()
-    def find_packages(
+    def find_packages(self, dependency):
-        self, name, constraint=None, extras=None, allow_prereleases=False
-    ):
        raise NotImplementedError()
    def search(self, query):

--- a/poetry/repositories/installed_repository.py
+++ b/poetry/repositories/installed_repository.py
@@ -76,9 +76,9 @@ class InstalledRepository(Repository):
        revision = git.rev_parse("HEAD", src).strip()
        url = git.remote_url(src)
-        package.source_type = "git"
+        package._source_type = "git"
-        package.source_url = url
+        package._source_url = url
-        package.source_reference = revision
+        package._source_reference = revision
    @classmethod
    def set_package_vcs_properties(cls, package, env):  # type: (Package, Env) -> None
@@ -144,15 +144,15 @@ class InstalledRepository(Repository):
                                    break
                            else:
                                # TODO: handle multiple source directories?
-                                package.source_type = "directory"
+                                package._source_type = "directory"
-                                package.source_url = paths.pop().as_posix()
+                                package._source_url = paths.pop().as_posix()
                    continue
                if cls.is_vcs_package(path, env):
                    cls.set_package_vcs_properties(package, env)
                else:
                    # If not, it's a path dependency
-                    package.source_type = "directory"
+                    package._source_type = "directory"
-                    package.source_url = str(path.parent)
+                    package._source_url = str(path.parent)
        return repo
--- a/poetry/repositories/legacy_repository.py
+++ b/poetry/repositories/legacy_repository.py
@@ -222,17 +222,17 @@ class LegacyRepository(PyPiRepository):
            path=parsed.path,
        )
-    def find_packages(
+    def find_packages(self, dependency):
-        self, name, constraint=None, extras=None, allow_prereleases=False
-    ):
        packages = []
+        constraint = dependency.constraint
        if constraint is None:
            constraint = "*"
        if not isinstance(constraint, VersionConstraint):
            constraint = parse_constraint(constraint)
+        allow_prereleases = dependency.allows_prereleases()
        if isinstance(constraint, VersionRange):
            if (
                constraint.max is not None
@@ -242,7 +242,7 @@ class LegacyRepository(PyPiRepository):
            ):
                allow_prereleases = True
-        key = name
+        key = dependency.name
        if not constraint.is_any():
            key = "{}:{}".format(key, str(constraint))
@@ -251,7 +251,7 @@ class LegacyRepository(PyPiRepository):
        if self._cache.store("matches").has(key):
            versions = self._cache.store("matches").get(key)
        else:
-            page = self._get("/{}/".format(canonicalize_name(name).replace(".", "-")))
+            page = self._get("/{}/".format(dependency.name.replace(".", "-")))
            if page is None:
                return []
@@ -270,19 +270,19 @@ class LegacyRepository(PyPiRepository):
        for package_versions in (versions, ignored_pre_release_versions):
            for version in package_versions:
-                package = Package(name, version)
+                package = Package(
-                package.source_type = "legacy"
+                    dependency.name,
-                package.source_reference = self.name
+                    version,
-                package.source_url = self._url
+                    source_type="legacy",
+                    source_reference=self.name,
-                if extras is not None:
+                    source_url=self._url,
-                    package.requires_extras = extras
+                )
                packages.append(package)
            self._log(
                "{} packages found for {} {}".format(
-                    len(packages), name, str(constraint)
+                    len(packages), dependency.name, str(constraint)
                ),
                level="debug",
            )
@@ -302,7 +302,7 @@ class LegacyRepository(PyPiRepository):
        We also need to download every file matching this release
        to get the various hashes.
-        Note that, this will be cached so the subsequent operations
+        Note that this will be cached so the subsequent operations
        should be much faster.
        """
        try:
@@ -311,9 +311,9 @@ class LegacyRepository(PyPiRepository):
            return self._packages[index]
        except ValueError:
            package = super(LegacyRepository, self).package(name, version, extras)
-            package.source_type = "legacy"
+            package._source_type = "legacy"
-            package.source_url = self._url
+            package._source_url = self._url
-            package.source_reference = self.name
+            package._source_reference = self.name
            return package

--- a/poetry/repositories/pool.py
+++ b/poetry/repositories/pool.py
@@ -144,13 +144,9 @@ class Pool(BaseRepository):
        raise PackageNotFound("Package {} ({}) not found.".format(name, version))
    def find_packages(
-        self,
+        self, dependency,
-        name,
-        constraint=None,
-        extras=None,
-        allow_prereleases=False,
-        repository=None,
    ):
+        repository = dependency.source_name
        if repository is not None:
            repository = repository.lower()
@@ -162,15 +158,11 @@ class Pool(BaseRepository):
            raise ValueError('Repository "{}" does not exist.'.format(repository))
        if repository is not None and not self._ignore_repository_names:
-            return self.repository(repository).find_packages(
+            return self.repository(repository).find_packages(dependency)
-                name, constraint, extras=extras, allow_prereleases=allow_prereleases
-            )
        packages = []
-        for idx, repo in enumerate(self._repositories):
+        for repo in self._repositories:
-            packages += repo.find_packages(
+            packages += repo.find_packages(dependency)
-                name, constraint, extras=extras, allow_prereleases=allow_prereleases
-            )
        return packages

--- a/poetry/repositories/pypi_repository.py
+++ b/poetry/repositories/pypi_repository.py
@@ -14,6 +14,7 @@ from cachecontrol.controller import logger as cache_control_logger
 from cachy import CacheManager
 from html5lib.html5parser import parse
+from poetry.core.packages import Dependency
 from poetry.core.packages import Package
 from poetry.core.packages import dependency_from_pep_508
 from poetry.core.packages.utils.link import Link
@@ -79,22 +80,18 @@ class PyPiRepository(RemoteRepository):
    def session(self):
        return self._session
-    def find_packages(
+    def find_packages(self, dependency):  # type: (Dependency) -> List[Package]
-        self,
-        name,  # type: str
-        constraint=None,  # type: Union[VersionConstraint, str, None]
-        extras=None,  # type: Union[list, None]
-        allow_prereleases=False,  # type: bool
-    ):  # type: (...) -> List[Package]
        """
        Find packages on the remote server.
        """
+        constraint = dependency.constraint
        if constraint is None:
            constraint = "*"
        if not isinstance(constraint, VersionConstraint):
            constraint = parse_constraint(constraint)
+        allow_prereleases = dependency.allows_prereleases()
        if isinstance(constraint, VersionRange):
            if (
                constraint.max is not None
@@ -105,10 +102,10 @@ class PyPiRepository(RemoteRepository):
                allow_prereleases = True
        try:
-            info = self.get_package_info(name)
+            info = self.get_package_info(dependency.name)
        except PackageNotFound:
            self._log(
-                "No packages found for {} {}".format(name, str(constraint)),
+                "No packages found for {} {}".format(dependency.name, str(constraint)),
                level="debug",
            )
            return []
@@ -121,7 +118,7 @@ class PyPiRepository(RemoteRepository):
                # Bad release
                self._log(
                    "No release information found for {}-{}, skipping".format(
-                        name, version
+                        dependency.name, version
                    ),
                    level="debug",
                )
@@ -132,7 +129,7 @@ class PyPiRepository(RemoteRepository):
            except ParseVersionError:
                self._log(
                    'Unable to parse version "{}" for the {} package, skipping'.format(
-                        version, name
+                        version, dependency.name
                    ),
                    level="debug",
                )
@@ -145,13 +142,12 @@ class PyPiRepository(RemoteRepository):
                continue
            if not constraint or (constraint and constraint.allows(package.version)):
-                if extras is not None:
-                    package.requires_extras = extras
                packages.append(package)
        self._log(
-            "{} packages found for {} {}".format(len(packages), name, str(constraint)),
+            "{} packages found for {} {}".format(
+                len(packages), dependency.name, str(constraint)
+            ),
            level="debug",
        )

--- a/poetry/repositories/repository.py
+++ b/poetry/repositories/repository.py
@@ -29,32 +29,22 @@ class Repository(BaseRepository):
        for package in self.packages:
            if name == package.name and package.version.text == version:
-                # Activate extra dependencies
+                package = package.with_features(extras)
-                for extra in extras:
-                    if extra in package.extras:
+                return package
-                        for extra_dep in package.extras[extra]:
-                            for dep in package.requires:
+    def find_packages(self, dependency):
-                                if dep.name == extra_dep.name:
+        constraint = dependency.constraint
-                                    dep.activate()
-                return package.clone()
-    def find_packages(
-        self, name, constraint=None, extras=None, allow_prereleases=False
-    ):
-        name = name.lower()
        packages = []
        ignored_pre_release_packages = []
-        if extras is None:
-            extras = []
        if constraint is None:
            constraint = "*"
        if not isinstance(constraint, VersionConstraint):
            constraint = parse_constraint(constraint)
+        allow_prereleases = dependency.allows_prereleases
        if isinstance(constraint, VersionRange):
            if (
                constraint.max is not None
@@ -65,7 +55,7 @@ class Repository(BaseRepository):
                allow_prereleases = True
        for package in self.packages:
-            if name == package.name:
+            if dependency.name == package.name:
                if (
                    package.is_prerelease()
                    and not allow_prereleases
@@ -79,19 +69,6 @@ class Repository(BaseRepository):
                    continue
                if constraint.allows(package.version):
-                    for dep in package.requires:
-                        for extra in extras:
-                            if extra not in package.extras:
-                                continue
-                            reqs = package.extras[extra]
-                            for req in reqs:
-                                if req.name == dep.name:
-                                    dep.activate()
-                    if extras:
-                        package.requires_extras = extras
                    packages.append(package)
        return packages or ignored_pre_release_packages

--- a/poetry/utils/exporter.py
+++ b/poetry/utils/exporter.py
+import os
 from typing import Union
 from clikit.api.io import IO
@@ -84,18 +86,35 @@ class Exporter(object):
                    package.source_url, package.source_reference, package.name
                )
            elif package.source_type in ["directory", "file", "url"]:
+                url = package.source_url
                if package.source_type == "file":
-                    dependency = FileDependency(package.name, Path(package.source_url))
+                    dependency = FileDependency(
+                        package.name,
+                        Path(package.source_url),
+                        base=self._poetry.locker.lock.path.parent,
+                    )
+                    url = Path(
+                        os.path.relpath(
+                            url, self._poetry.locker.lock.path.parent.as_posix()
+                        )
+                    ).as_posix()
                elif package.source_type == "directory":
                    dependency = DirectoryDependency(
-                        package.name, Path(package.source_url)
+                        package.name,
+                        Path(package.source_url),
+                        base=self._poetry.locker.lock.path.parent,
                    )
+                    url = Path(
+                        os.path.relpath(
+                            url, self._poetry.locker.lock.path.parent.as_posix()
+                        )
+                    ).as_posix()
                else:
                    dependency = URLDependency(package.name, package.source_url)
                dependency.marker = package.marker
-                line = "{}".format(package.source_url)
+                line = "{}".format(url)
                if package.develop and package.source_type == "directory":
                    line = "-e " + line
            else:

--- a/poetry/utils/helpers.py
+++ b/poetry/utils/helpers.py
@@ -10,6 +10,7 @@ from typing import Optional
 import requests
 from poetry.config.config import Config
+from poetry.core.packages.package import Package
 from poetry.core.version import Version
 from poetry.utils._compat import Path
@@ -100,3 +101,15 @@ def download_file(
            for chunk in response.iter_content(chunk_size=chunk_size):
                if chunk:
                    f.write(chunk)
+def get_package_version_display_string(
+    package, root=None
+):  # type: (Package, Optional[Path]) -> str
+    if package.source_type in ["file", "directory"] and root:
+        return "{} {}".format(
+            package.version,
+            Path(os.path.relpath(package.source_url, root.as_posix())).as_posix(),
+        )
+    return package.full_pretty_version
--- a/poetry/version/version_selector.py
+++ b/poetry/version/version_selector.py
 from typing import Union
-from poetry.core.packages import Dependency
 from poetry.core.packages import Package
 from poetry.core.semver import Version
-from poetry.core.semver import parse_constraint
 class VersionSelector(object):
@@ -21,27 +19,27 @@ class VersionSelector(object):
        Given a package name and optional version,
        returns the latest Package that matches
        """
-        if target_package_version:
+        from poetry.factory import Factory
-            constraint = parse_constraint(target_package_version)
-        else:
+        dependency = Factory.create_dependency(
-            constraint = parse_constraint("*")
+            package_name,
+            {
-        candidates = self._pool.find_packages(
+                "version": target_package_version or "*",
-            package_name, constraint, allow_prereleases=True, repository=source
+                "allow_prereleases": allow_prereleases,
+                "source": source,
+            },
        )
+        candidates = self._pool.find_packages(dependency)
        only_prereleases = all([c.version.is_prerelease() for c in candidates])
        if not candidates:
            return False
-        dependency = Dependency(package_name, constraint)
        package = None
        for candidate in candidates:
            if (
                candidate.is_prerelease()
                and not dependency.allows_prereleases()
-                and not allow_prereleases
                and not only_prereleases
            ):
                continue

--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,7 +24,7 @@ classifiers = [
 [tool.poetry.dependencies]
 python = "~2.7 || ^3.5"
-poetry-core = "^1.0.0a9"
+poetry-core = "^1.0.0b1"
 cleo = "^0.8.1"
 clikit = "^0.6.2"
 crashtest = { version = "^0.3.0", python = "^3.6" }

--- a/tests/console/commands/debug/test_resolve.py
+++ b/tests/console/commands/debug/test_resolve.py
 from cleo.testers import CommandTester
+from poetry.factory import Factory
 from tests.helpers import get_package
@@ -8,7 +9,7 @@ def test_debug_resolve_gives_resolution_results(app, repo):
    tester = CommandTester(command)
    cachy2 = get_package("cachy", "0.2.0")
-    cachy2.add_dependency("msgpack-python", ">=0.5 <0.6")
+    cachy2.add_dependency(Factory.create_dependency("msgpack-python", ">=0.5 <0.6"))
    repo.add_package(get_package("cachy", "0.1.0"))
    repo.add_package(cachy2)
@@ -33,7 +34,7 @@ def test_debug_resolve_tree_option_gives_the_dependency_tree(app, repo):
    tester = CommandTester(command)
    cachy2 = get_package("cachy", "0.2.0")
-    cachy2.add_dependency("msgpack-python", ">=0.5 <0.6")
+    cachy2.add_dependency(Factory.create_dependency("msgpack-python", ">=0.5 <0.6"))
    repo.add_package(get_package("cachy", "0.1.0"))
    repo.add_package(cachy2)

--- a/tests/console/commands/test_add.py
+++ b/tests/console/commands/test_add.py
@@ -300,12 +300,13 @@ Package operations: 2 installs, 0 updates, 0 removals
 def test_add_directory_constraint(app, repo, tester, mocker):
    p = mocker.patch("poetry.utils._compat.Path.cwd")
-    p.return_value = Path(__file__) / ".."
+    p.return_value = Path(__file__).parent
    repo.add_package(get_package("pendulum", "1.4.4"))
    repo.add_package(get_package("cleo", "0.6.5"))
-    tester.execute("../git/github.com/demo/demo")
+    path = "../git/github.com/demo/demo"
+    tester.execute("{}".format(path))
    expected = """\
@@ -317,8 +318,10 @@ Writing lock file
 Package operations: 2 installs, 0 updates, 0 removals
  • Installing pendulum (1.4.4)
-  • Installing demo (0.1.2 ../git/github.com/demo/demo)
+  • Installing demo (0.1.2 {})
-"""
+""".format(
+        app.poetry.file.parent.joinpath(path).resolve().as_posix()
+    )
    assert expected == tester.io.fetch_output()
    assert 2 == tester._command.installer.executor.installations_count
@@ -335,7 +338,8 @@ def test_add_directory_with_poetry(app, repo, tester, mocker):
    repo.add_package(get_package("pendulum", "1.4.4"))
-    tester.execute("../git/github.com/demo/pyproject-demo")
+    path = "../git/github.com/demo/pyproject-demo"
+    tester.execute("{}".format(path))
    expected = """\
@@ -347,8 +351,10 @@ Writing lock file
 Package operations: 2 installs, 0 updates, 0 removals
  • Installing pendulum (1.4.4)
-  • Installing demo (0.1.2 ../git/github.com/demo/pyproject-demo)
+  • Installing demo (0.1.2 {})
-"""
+""".format(
+        app.poetry.file.parent.joinpath(path).resolve().as_posix()
+    )
    assert expected == tester.io.fetch_output()
    assert 2 == tester._command.installer.executor.installations_count
@@ -360,7 +366,8 @@ def test_add_file_constraint_wheel(app, repo, tester, mocker, poetry):
    repo.add_package(get_package("pendulum", "1.4.4"))
-    tester.execute("../distributions/demo-0.1.0-py2.py3-none-any.whl")
+    path = "../distributions/demo-0.1.0-py2.py3-none-any.whl"
+    tester.execute("{}".format(path))
    expected = """\
@@ -372,8 +379,10 @@ Writing lock file
 Package operations: 2 installs, 0 updates, 0 removals
  • Installing pendulum (1.4.4)
-  • Installing demo (0.1.0 ../distributions/demo-0.1.0-py2.py3-none-any.whl)
+  • Installing demo (0.1.0 {})
-"""
+""".format(
+        app.poetry.file.parent.joinpath(path).resolve().as_posix()
+    )
    assert expected == tester.io.fetch_output()
    assert 2 == tester._command.installer.executor.installations_count
@@ -392,7 +401,8 @@ def test_add_file_constraint_sdist(app, repo, tester, mocker):
    repo.add_package(get_package("pendulum", "1.4.4"))
-    tester.execute("../distributions/demo-0.1.0.tar.gz")
+    path = "../distributions/demo-0.1.0.tar.gz"
+    tester.execute("{}".format(path))
    expected = """\
@@ -404,8 +414,10 @@ Writing lock file
 Package operations: 2 installs, 0 updates, 0 removals
  • Installing pendulum (1.4.4)
-  • Installing demo (0.1.0 ../distributions/demo-0.1.0.tar.gz)
+  • Installing demo (0.1.0 {})
-"""
+""".format(
+        app.poetry.file.parent.joinpath(path).resolve().as_posix()
+    )
    assert expected == tester.io.fetch_output()
    assert 2 == tester._command.installer.executor.installations_count
@@ -1076,7 +1088,8 @@ def test_add_directory_constraint_old_installer(
    repo.add_package(get_package("pendulum", "1.4.4"))
    repo.add_package(get_package("cleo", "0.6.5"))
-    old_tester.execute("../git/github.com/demo/demo")
+    path = "../git/github.com/demo/demo"
+    old_tester.execute("{}".format(path))
    expected = """\
@@ -1088,8 +1101,10 @@ Writing lock file
 Package operations: 2 installs, 0 updates, 0 removals
  - Installing pendulum (1.4.4)
-  - Installing demo (0.1.2 ../git/github.com/demo/demo)
+  - Installing demo (0.1.2 {})
-"""
+""".format(
+        app.poetry.file.parent.joinpath(path).resolve().as_posix()
+    )
    assert expected == old_tester.io.fetch_output()
@@ -1109,7 +1124,8 @@ def test_add_directory_with_poetry_old_installer(
    repo.add_package(get_package("pendulum", "1.4.4"))
-    old_tester.execute("../git/github.com/demo/pyproject-demo")
+    path = "../git/github.com/demo/pyproject-demo"
+    old_tester.execute("{}".format(path))
    expected = """\
@@ -1121,8 +1137,10 @@ Writing lock file
 Package operations: 2 installs, 0 updates, 0 removals
  - Installing pendulum (1.4.4)
-  - Installing demo (0.1.2 ../git/github.com/demo/pyproject-demo)
+  - Installing demo (0.1.2 {})
-"""
+""".format(
+        app.poetry.file.parent.joinpath(path).resolve().as_posix()
+    )
    assert expected == old_tester.io.fetch_output()
@@ -1137,7 +1155,8 @@ def test_add_file_constraint_wheel_old_installer(
    repo.add_package(get_package("pendulum", "1.4.4"))
-    old_tester.execute("../distributions/demo-0.1.0-py2.py3-none-any.whl")
+    path = "../distributions/demo-0.1.0-py2.py3-none-any.whl"
+    old_tester.execute("{}".format(path))
    expected = """\
@@ -1149,8 +1168,10 @@ Writing lock file
 Package operations: 2 installs, 0 updates, 0 removals
  - Installing pendulum (1.4.4)
-  - Installing demo (0.1.0 ../distributions/demo-0.1.0-py2.py3-none-any.whl)
+  - Installing demo (0.1.0 {})
-"""
+""".format(
+        app.poetry.file.parent.joinpath(path).resolve().as_posix()
+    )
    assert expected == old_tester.io.fetch_output()
@@ -1172,7 +1193,8 @@ def test_add_file_constraint_sdist_old_installer(
    repo.add_package(get_package("pendulum", "1.4.4"))
-    old_tester.execute("../distributions/demo-0.1.0.tar.gz")
+    path = "../distributions/demo-0.1.0.tar.gz"
+    old_tester.execute("{}".format(path))
    expected = """\
@@ -1184,8 +1206,10 @@ Writing lock file
 Package operations: 2 installs, 0 updates, 0 removals
  - Installing pendulum (1.4.4)
-  - Installing demo (0.1.0 ../distributions/demo-0.1.0.tar.gz)
+  - Installing demo (0.1.0 {})
-"""
+""".format(
+        app.poetry.file.parent.joinpath(path).resolve().as_posix()
+    )
    assert expected == old_tester.io.fetch_output()

--- a/tests/console/commands/test_show.py
+++ b/tests/console/commands/test_show.py
@@ -3,6 +3,7 @@ import pytest
 from cleo.testers import CommandTester
 from clikit.formatter.ansi_formatter import AnsiFormatter
+from poetry.factory import Factory
 from tests.helpers import get_package
@@ -1067,10 +1068,10 @@ def test_show_tree(app, poetry, installed):
    command = app.find("show")
    tester = CommandTester(command)
-    poetry.package.add_dependency("cachy", "^0.2.0")
+    poetry.package.add_dependency(Factory.create_dependency("cachy", "^0.2.0"))
    cachy2 = get_package("cachy", "0.2.0")
-    cachy2.add_dependency("msgpack-python", ">=0.5 <0.6")
+    cachy2.add_dependency(Factory.create_dependency("msgpack-python", ">=0.5 <0.6"))
    installed.add_package(cachy2)

--- a/tests/console/conftest.py
+++ b/tests/console/conftest.py
@@ -181,14 +181,11 @@ class Poetry(BasePoetry):
 class Repository(BaseRepository):
-    def find_packages(
+    def find_packages(self, dependency):
-        self, name, constraint=None, extras=None, allow_prereleases=False
+        packages = super(Repository, self).find_packages(dependency)
-    ):
-        packages = super(Repository, self).find_packages(
-            name, constraint, extras, allow_prereleases
-        )
        if len(packages) == 0:
-            raise PackageNotFound("Package [{}] not found.".format(name))
+            raise PackageNotFound("Package [{}] not found.".format(dependency.name))
        return packages
    def find_links_for_package(self, package):

--- a/tests/installation/fixtures/with-directory-dependency-poetry-transitive.test
+++ b/tests/installation/fixtures/with-directory-dependency-poetry-transitive.test
@@ -14,23 +14,21 @@ bar = ["tomlkit"]
 foo = ["cleo"]
 [package.source]
-reference = ""
 type = "file"
-url = "../../distributions/demo-0.1.0-py2.py3-none-any.whl"
+url = "../distributions/demo-0.1.0-py2.py3-none-any.whl"
 [[package]]
 category = "main"
 description = "This is a description"
-develop = true
+develop = false
 name = "inner-directory-project"
 optional = false
 python-versions = "*"
 version = "1.2.4"
 [package.source]
-reference = ""
 type = "directory"
-url = "../project_with_transitive_file_dependencies/inner-directory-project"
+url = "project_with_transitive_file_dependencies/inner-directory-project"
 [[package]]
 category = "main"
@@ -43,7 +41,7 @@ version = "1.4.4"
 [[package]]
 category = "main"
 description = "This is a description"
-develop = true
+develop = false
 name = "project-with-extras"
 optional = false
 python-versions = "*"
@@ -54,14 +52,13 @@ extras_a = ["pendulum (>=1.4.4)"]
 extras_b = ["cachy (>=0.2.0)"]
 [package.source]
-reference = ""
 type = "directory"
 url = "../project_with_extras"
 [[package]]
 category = "main"
 description = "This is a description"
-develop = true
+develop = false
 name = "project-with-transitive-directory-dependencies"
 optional = false
 python-versions = "*"
@@ -72,14 +69,13 @@ project-with-extras = "1.2.3"
 project-with-transitive-file-dependencies = "1.2.3"
 [package.source]
-reference = ""
 type = "directory"
 url = "project_with_transitive_directory_dependencies"
 [[package]]
 category = "main"
 description = "This is a description"
-develop = true
+develop = false
 name = "project-with-transitive-file-dependencies"
 optional = false
 python-versions = "*"
@@ -90,7 +86,6 @@ demo = "0.1.0"
 inner-directory-project = "1.2.4"
 [package.source]
-reference = ""
 type = "directory"
 url = "project_with_transitive_file_dependencies"

--- a/tests/installation/fixtures/with-directory-dependency-poetry.test
+++ b/tests/installation/fixtures/with-directory-dependency-poetry.test
@@ -9,7 +9,7 @@ version = "1.4.4"
 [[package]]
 category = "main"
 description = "This is a description"
-develop = true
+develop = false
 name = "project-with-extras"
 optional = false
 python-versions = "*"
@@ -23,7 +23,6 @@ extras_a = ["pendulum (>=1.4.4)"]
 extras_b = ["cachy (>=0.2.0)"]
 [package.source]
-reference = ""
 type = "directory"
 url = "tests/fixtures/project_with_extras"

--- a/tests/installation/fixtures/with-directory-dependency-setuptools.test
+++ b/tests/installation/fixtures/with-directory-dependency-setuptools.test
@@ -9,7 +9,7 @@ python-versions = "*"
 [[package]]
 name = "my-package"
 version = "0.1.2"
-develop = true
+develop = false
 description = "Demo project."
 category = "main"
 optional = false
@@ -17,7 +17,6 @@ python-versions = "*"
 [package.source]
 type = "directory"
-reference = ""
 url = "tests/fixtures/project_with_setup"
 [package.dependencies]

--- a/tests/installation/fixtures/with-file-dependency-transitive.test
+++ b/tests/installation/fixtures/with-file-dependency-transitive.test
@@ -14,21 +14,19 @@ bar = ["tomlkit"]
 foo = ["cleo"]
 [package.source]
-reference = ""
 type = "file"
 url = "../distributions/demo-0.1.0-py2.py3-none-any.whl"
 [[package]]
 category = "main"
 description = "This is a description"
-develop = true
+develop = false
 name = "inner-directory-project"
 optional = false
 python-versions = "*"
 version = "1.2.4"
 [package.source]
-reference = ""
 type = "directory"
 url = "project_with_transitive_file_dependencies/inner-directory-project"
@@ -43,7 +41,7 @@ version = "1.4.4"
 [[package]]
 category = "main"
 description = "This is a description"
-develop = true
+develop = false
 name = "project-with-transitive-file-dependencies"
 optional = false
 python-versions = "*"
@@ -54,7 +52,6 @@ demo = "0.1.0"
 inner-directory-project = "1.2.4"
 [package.source]
-reference = ""
 type = "directory"
 url = "project_with_transitive_file_dependencies"

--- a/tests/installation/fixtures/with-file-dependency.test
+++ b/tests/installation/fixtures/with-file-dependency.test
@@ -8,7 +8,6 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 [package.source]
 type = "file"
-reference = ""
 url = "tests/fixtures/distributions/demo-0.1.0-py2.py3-none-any.whl"
 [package.dependencies]

--- a/tests/installation/fixtures/with-url-dependency.test
+++ b/tests/installation/fixtures/with-url-dependency.test
@@ -8,7 +8,6 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 [package.source]
 type = "url"
-reference = ""
 url = "https://python-poetry.org/distributions/demo-0.1.0-py2.py3-none-any.whl"
 [package.dependencies]

--- a/tests/installation/fixtures/with-wheel-dependency-no-requires-dist.test
+++ b/tests/installation/fixtures/with-wheel-dependency-no-requires-dist.test
@@ -8,7 +8,6 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 [package.source]
 type = "file"
-reference = ""
 url = "tests/fixtures/wheel_with_no_requires_dist/demo-0.1.0-py2.py3-none-any.whl"
 [metadata]

--- a/tests/installation/test_chooser.py
+++ b/tests/installation/test_chooser.py
@@ -89,9 +89,13 @@ def test_chooser_chooses_universal_wheel_link_if_available(
    package = Package("pytest", "3.5.0")
    if source_type == "legacy":
-        package.source_type = "legacy"
+        package = Package(
-        package.source_reference = "foo"
+            package.name,
-        package.source_url = "https://foo.bar/simple/"
+            package.version.text,
+            source_type="legacy",
+            source_reference="foo",
+            source_url="https://foo.bar/simple/",
+        )
    link = chooser.choose_for(package)
@@ -106,9 +110,13 @@ def test_chooser_chooses_specific_python_universal_wheel_link_if_available(
    package = Package("isort", "4.3.4")
    if source_type == "legacy":
-        package.source_type = "legacy"
+        package = Package(
-        package.source_reference = "foo"
+            package.name,
-        package.source_url = "https://foo.bar/simple/"
+            package.version.text,
+            source_type="legacy",
+            source_reference="foo",
+            source_url="https://foo.bar/simple/",
+        )
    link = chooser.choose_for(package)
@@ -126,9 +134,13 @@ def test_chooser_chooses_system_specific_wheel_link_if_available(
    package = Package("pyyaml", "3.13.0")
    if source_type == "legacy":
-        package.source_type = "legacy"
+        package = Package(
-        package.source_reference = "foo"
+            package.name,
-        package.source_url = "https://foo.bar/simple/"
+            package.version.text,
+            source_type="legacy",
+            source_reference="foo",
+            source_url="https://foo.bar/simple/",
+        )
    link = chooser.choose_for(package)
@@ -143,9 +155,13 @@ def test_chooser_chooses_sdist_if_no_compatible_wheel_link_is_available(
    package = Package("pyyaml", "3.13.0")
    if source_type == "legacy":
-        package.source_type = "legacy"
+        package = Package(
-        package.source_reference = "foo"
+            package.name,
-        package.source_url = "https://foo.bar/simple/"
+            package.version.text,
+            source_type="legacy",
+            source_reference="foo",
+            source_url="https://foo.bar/simple/",
+        )
    link = chooser.choose_for(package)
@@ -159,16 +175,22 @@ def test_chooser_chooses_distributions_that_match_the_package_hashes(
    chooser = Chooser(pool, env)
    package = Package("isort", "4.3.4")
-    package.files = [
+    files = [
        {
            "hash": "sha256:b9c40e9750f3d77e6e4d441d8b0266cf555e7cdabdcff33c4fd06366ca761ef8",
            "filename": "isort-4.3.4.tar.gz",
        }
    ]
    if source_type == "legacy":
-        package.source_type = "legacy"
+        package = Package(
-        package.source_reference = "foo"
+            package.name,
-        package.source_url = "https://foo.bar/simple/"
+            package.version.text,
+            source_type="legacy",
+            source_reference="foo",
+            source_url="https://foo.bar/simple/",
+        )
+    package.files = files
    link = chooser.choose_for(package)

--- a/tests/installation/test_executor.py
+++ b/tests/installation/test_executor.py
@@ -65,26 +65,35 @@ def test_execute_executes_a_batch_of_operations(
    env = MockEnv(path=Path(tmp_dir))
    executor = Executor(env, pool, config, io)
-    file_package = Package("demo", "0.1.0")
+    file_package = Package(
-    file_package.source_type = "file"
+        "demo",
-    file_package.source_url = str(
+        "0.1.0",
-        Path(__file__)
+        source_type="file",
+        source_url=Path(__file__)
        .parent.parent.joinpath(
            "fixtures/distributions/demo-0.1.0-py2.py3-none-any.whl"
        )
        .resolve()
+        .as_posix(),
    )
-    directory_package = Package("simple-project", "1.2.3")
+    directory_package = Package(
-    directory_package.source_type = "directory"
+        "simple-project",
-    directory_package.source_url = str(
+        "1.2.3",
-        Path(__file__).parent.parent.joinpath("fixtures/simple_project").resolve()
+        source_type="directory",
+        source_url=Path(__file__)
+        .parent.parent.joinpath("fixtures/simple_project")
+        .resolve()
+        .as_posix(),
    )
-    git_package = Package("demo", "0.1.0")
+    git_package = Package(
-    git_package.source_type = "git"
+        "demo",
-    git_package.source_reference = "master"
+        "0.1.0",
-    git_package.source_url = "https://github.com/demo/demo.git"
+        source_type="git",
+        source_reference="master",
+        source_url="https://github.com/demo/demo.git",
+    )
    assert 0 == executor.execute(
        [

--- a/tests/installation/test_installer.py
+++ b/tests/installation/test_installer.py
 from __future__ import unicode_literals
+import json
 import sys
 import pytest
@@ -7,6 +8,7 @@ import pytest
 from clikit.io import NullIO
 from poetry.core.packages import ProjectPackage
+from poetry.factory import Factory
 from poetry.installation import Installer as BaseInstaller
 from poetry.installation.executor import Executor as BaseExecutor
 from poetry.installation.noop_installer import NoopInstaller
@@ -79,6 +81,7 @@ class CustomInstalledRepository(InstalledRepository):
 class Locker(BaseLocker):
    def __init__(self):
+        self._lock = TomlFile(Path.cwd().joinpath("poetry.lock"))
        self._written_data = None
        self._locked = False
        self._content_hash = self._get_content_hash()
@@ -87,6 +90,11 @@ class Locker(BaseLocker):
    def written_data(self):
        return self._written_data
+    def set_lock_path(self, lock):
+        self._lock = TomlFile(Path(lock).joinpath("poetry.lock"))
+        return self
    def locked(self, is_locked=True):
        self._locked = is_locked
@@ -118,7 +126,7 @@ class Locker(BaseLocker):
            package["python-versions"] = python_versions
-        self._written_data = data
+        self._written_data = json.loads(json.dumps(data))
        self._lock_data = data
@@ -178,7 +186,7 @@ def installer(package, pool, locker, env, installed, config):
 def fixture(name):
    file = TomlFile(Path(__file__).parent / "fixtures" / "{}.test".format(name))
-    return file.read()
+    return json.loads(json.dumps(file.read()))
 def test_run_no_dependencies(installer, locker):
@@ -194,8 +202,8 @@ def test_run_with_dependencies(installer, locker, repo, package):
    repo.add_package(package_a)
    repo.add_package(package_b)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
    installer.run()
    expected = fixture("with-dependencies")
@@ -257,8 +265,8 @@ def test_run_update_after_removing_dependencies(
    installed.add_package(package_b)
    installed.add_package(package_c)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "~1.1")
+    package.add_dependency(Factory.create_dependency("B", "~1.1"))
    installer.update(True)
    installer.run()
@@ -323,9 +331,9 @@ def test_run_install_no_dev(installer, locker, repo, package, installed):
    installed.add_package(package_b)
    installed.add_package(package_c)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "~1.1")
+    package.add_dependency(Factory.create_dependency("B", "~1.1"))
-    package.add_dependency("C", "~1.2", category="dev")
+    package.add_dependency(Factory.create_dependency("C", "~1.2", category="dev"))
    installer.dev_mode(False)
    installer.run()
@@ -373,7 +381,7 @@ def test_run_install_remove_untracked(installer, locker, repo, package, installe
    installed.add_package(package_pip)  # Always required and never removed.
    installed.add_package(package)  # Root package never removed.
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
    installer.dev_mode(True).remove_untracked(True)
    installer.run()
@@ -414,8 +422,8 @@ def test_run_whitelist_add(installer, locker, repo, package):
    repo.add_package(package_a_new)
    repo.add_package(package_b)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
    installer.update(True)
    installer.whitelist(["B"])
@@ -464,7 +472,7 @@ def test_run_whitelist_remove(installer, locker, repo, package, installed):
    repo.add_package(package_b)
    installed.add_package(package_b)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
    installer.update(True)
    installer.whitelist(["B"])
@@ -488,11 +496,11 @@ def test_add_with_sub_dependencies(installer, locker, repo, package):
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package_a.add_dependency("D", "^1.0")
+    package_a.add_dependency(Factory.create_dependency("D", "^1.0"))
-    package_b.add_dependency("C", "~1.2")
+    package_b.add_dependency(Factory.create_dependency("C", "~1.2"))
    installer.run()
    expected = fixture("with-sub-dependencies")
@@ -515,9 +523,9 @@ def test_run_with_python_versions(installer, locker, repo, package):
    repo.add_package(package_c12)
    repo.add_package(package_c13)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", "^1.0")
+    package.add_dependency(Factory.create_dependency("C", "^1.0"))
    installer.run()
    expected = fixture("with-python-versions")
@@ -535,7 +543,7 @@ def test_run_with_optional_and_python_restricted_dependencies(
    package_c12 = get_package("C", "1.2")
    package_c13 = get_package("C", "1.3")
    package_d = get_package("D", "1.4")
-    package_c13.add_dependency("D", "^1.2")
+    package_c13.add_dependency(Factory.create_dependency("D", "^1.2"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -544,9 +552,15 @@ def test_run_with_optional_and_python_restricted_dependencies(
    repo.add_package(package_d)
    package.extras = {"foo": [get_dependency("A", "~1.0")]}
-    package.add_dependency("A", {"version": "~1.0", "optional": True})
+    package.add_dependency(
-    package.add_dependency("B", {"version": "^1.0", "python": "~2.4"})
+        Factory.create_dependency("A", {"version": "~1.0", "optional": True})
-    package.add_dependency("C", {"version": "^1.0", "python": "~2.7 || ^3.4"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "python": "~2.4"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "python": "~2.7 || ^3.4"})
+    )
    installer.run()
    expected = fixture("with-optional-dependencies")
@@ -571,7 +585,7 @@ def test_run_with_optional_and_platform_restricted_dependencies(
    package_c12 = get_package("C", "1.2")
    package_c13 = get_package("C", "1.3")
    package_d = get_package("D", "1.4")
-    package_c13.add_dependency("D", "^1.2")
+    package_c13.add_dependency(Factory.create_dependency("D", "^1.2"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -580,9 +594,15 @@ def test_run_with_optional_and_platform_restricted_dependencies(
    repo.add_package(package_d)
    package.extras = {"foo": [get_dependency("A", "~1.0")]}
-    package.add_dependency("A", {"version": "~1.0", "optional": True})
+    package.add_dependency(
-    package.add_dependency("B", {"version": "^1.0", "platform": "custom"})
+        Factory.create_dependency("A", {"version": "~1.0", "optional": True})
-    package.add_dependency("C", {"version": "^1.0", "platform": "darwin"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "platform": "custom"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "platform": "darwin"})
+    )
    installer.run()
    expected = fixture("with-platform-dependencies")
@@ -603,14 +623,18 @@ def test_run_with_dependencies_extras(installer, locker, repo, package):
    package_c = get_package("C", "1.0")
    package_b.extras = {"foo": [get_dependency("C", "^1.0")]}
-    package_b.add_dependency("C", {"version": "^1.0", "optional": True})
+    package_b.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
    repo.add_package(package_a)
    repo.add_package(package_b)
    repo.add_package(package_c)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", {"version": "^1.0", "extras": ["foo"]})
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "extras": ["foo"]})
+    )
    installer.run()
    expected = fixture("with-dependencies-extras")
@@ -630,10 +654,12 @@ def test_run_does_not_install_extras_if_not_requested(installer, locker, repo, p
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", "^1.0")
+    package.add_dependency(Factory.create_dependency("C", "^1.0"))
-    package.add_dependency("D", {"version": "^1.0", "optional": True})
+    package.add_dependency(
+        Factory.create_dependency("D", {"version": "^1.0", "optional": True})
+    )
    installer.run()
    expected = fixture("extras")
@@ -657,10 +683,12 @@ def test_run_installs_extras_if_requested(installer, locker, repo, package):
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", "^1.0")
+    package.add_dependency(Factory.create_dependency("C", "^1.0"))
-    package.add_dependency("D", {"version": "^1.0", "optional": True})
+    package.add_dependency(
+        Factory.create_dependency("D", {"version": "^1.0", "optional": True})
+    )
    installer.extras(["foo"])
    installer.run()
@@ -685,11 +713,13 @@ def test_run_installs_extras_with_deps_if_requested(installer, locker, repo, pac
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", {"version": "^1.0", "optional": True})
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
-    package_c.add_dependency("D", "^1.0")
+    package_c.add_dependency(Factory.create_dependency("D", "^1.0"))
    installer.extras(["foo"])
    installer.run()
@@ -718,11 +748,13 @@ def test_run_installs_extras_with_deps_if_requested_locked(
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", {"version": "^1.0", "optional": True})
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
-    package_c.add_dependency("D", "^1.0")
+    package_c.add_dependency(Factory.create_dependency("D", "^1.0"))
    installer.extras(["foo"])
    installer.run()
@@ -739,7 +771,7 @@ def test_installer_with_pypi_repository(package, locker, installed, config):
        NullIO(), NullEnv(), package, locker, pool, config, installed=installed
    )
-    package.add_dependency("pytest", "^3.5", category="dev")
+    package.add_dependency(Factory.create_dependency("pytest", "^3.5", category="dev"))
    installer.run()
    expected = fixture("with-pypi-repository")
@@ -749,7 +781,7 @@ def test_installer_with_pypi_repository(package, locker, installed, config):
 def test_run_installs_with_local_file(installer, locker, repo, package):
    file_path = fixtures_dir / "distributions/demo-0.1.0-py2.py3-none-any.whl"
-    package.add_dependency("demo", {"file": str(file_path)})
+    package.add_dependency(Factory.create_dependency("demo", {"file": str(file_path)}))
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -758,7 +790,6 @@ def test_run_installs_with_local_file(installer, locker, repo, package):
    expected = fixture("with-file-dependency")
    assert locker.written_data == expected
    assert 2 == installer.executor.installations_count
@@ -766,7 +797,7 @@ def test_run_installs_wheel_with_no_requires_dist(installer, locker, repo, packa
    file_path = (
        fixtures_dir / "wheel_with_no_requires_dist/demo-0.1.0-py2.py3-none-any.whl"
    )
-    package.add_dependency("demo", {"file": str(file_path)})
+    package.add_dependency(Factory.create_dependency("demo", {"file": str(file_path)}))
    installer.run()
@@ -782,8 +813,11 @@ def test_run_installs_with_local_poetry_directory_and_extras(
 ):
    file_path = fixtures_dir / "project_with_extras"
    package.add_dependency(
-        "project-with-extras", {"path": str(file_path), "extras": ["extras_a"]}
+        Factory.create_dependency(
+            "project-with-extras", {"path": str(file_path), "extras": ["extras_a"]}
+        )
    )
+    print(package.requires[0].develop)
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -799,13 +833,16 @@ def test_run_installs_with_local_poetry_directory_and_extras(
 def test_run_installs_with_local_poetry_directory_transitive(
    installer, locker, repo, package, tmpdir
 ):
-    package.root_dir = fixtures_dir.joinpath("directory")
+    root_dir = fixtures_dir.joinpath("directory")
-    directory = fixtures_dir.joinpath("directory").joinpath(
+    package.root_dir = root_dir
-        "project_with_transitive_directory_dependencies"
+    locker.set_lock_path(root_dir)
-    )
+    directory = root_dir.joinpath("project_with_transitive_directory_dependencies")
    package.add_dependency(
-        "project-with-transitive-directory-dependencies",
+        Factory.create_dependency(
-        {"path": str(directory.relative_to(fixtures_dir.joinpath("directory")))},
+            "project-with-transitive-directory-dependencies",
+            {"path": str(directory.relative_to(root_dir))},
+            root_dir=root_dir,
+        )
    )
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -823,13 +860,18 @@ def test_run_installs_with_local_poetry_directory_transitive(
 def test_run_installs_with_local_poetry_file_transitive(
    installer, locker, repo, package, tmpdir
 ):
-    package.root_dir = fixtures_dir.joinpath("directory")
+    root_dir = fixtures_dir.joinpath("directory")
+    package.root_dir = root_dir
+    locker.set_lock_path(root_dir)
    directory = fixtures_dir.joinpath("directory").joinpath(
        "project_with_transitive_file_dependencies"
    )
    package.add_dependency(
-        "project-with-transitive-file-dependencies",
+        Factory.create_dependency(
-        {"path": str(directory.relative_to(fixtures_dir.joinpath("directory")))},
+            "project-with-transitive-file-dependencies",
+            {"path": str(directory.relative_to(root_dir))},
+            root_dir=root_dir,
+        )
    )
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -848,7 +890,9 @@ def test_run_installs_with_local_setuptools_directory(
    installer, locker, repo, package, tmpdir
 ):
    file_path = fixtures_dir / "project_with_setup/"
-    package.add_dependency("my-package", {"path": str(file_path)})
+    package.add_dependency(
+        Factory.create_dependency("my-package", {"path": str(file_path)})
+    )
    repo.add_package(get_package("pendulum", "1.4.4"))
    repo.add_package(get_package("cachy", "0.2.0"))
@@ -858,7 +902,6 @@ def test_run_installs_with_local_setuptools_directory(
    expected = fixture("with-directory-dependency-setuptools")
    assert locker.written_data == expected
    assert 3 == installer.executor.installations_count
@@ -890,8 +933,10 @@ def test_run_with_prereleases(installer, locker, repo, package):
    repo.add_package(package_a)
    repo.add_package(package_b)
-    package.add_dependency("A", {"version": "*", "allow-prereleases": True})
+    package.add_dependency(
-    package.add_dependency("B", "^1.1")
+        Factory.create_dependency("A", {"version": "*", "allow-prereleases": True})
+    )
+    package.add_dependency(Factory.create_dependency("B", "^1.1"))
    installer.update(True)
    installer.whitelist({"B": "^1.1"})
@@ -927,12 +972,16 @@ def test_run_changes_category_if_needed(installer, locker, repo, package):
    )
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.1")
-    package_b.add_dependency("A", "^1.0")
+    package_b.add_dependency(Factory.create_dependency("A", "^1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
-    package.add_dependency("A", {"version": "^1.0", "optional": True}, category="dev")
+    package.add_dependency(
-    package.add_dependency("B", "^1.1")
+        Factory.create_dependency(
+            "A", {"version": "^1.0", "optional": True}, category="dev"
+        )
+    )
+    package.add_dependency(Factory.create_dependency("B", "^1.1"))
    installer.update(True)
    installer.whitelist(["B"])
@@ -970,7 +1019,7 @@ def test_run_update_all_with_lock(installer, locker, repo, package):
    repo.add_package(get_package("A", "1.0"))
    repo.add_package(package_a)
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    installer.update(True)
@@ -1037,8 +1086,10 @@ def test_run_update_with_locked_extras(installer, locker, repo, package):
    repo.add_package(get_package("C", "1.1"))
    repo.add_package(get_package("D", "1.1"))
-    package.add_dependency("A", {"version": "^1.0", "extras": ["foo"]})
+    package.add_dependency(
-    package.add_dependency("D", "^1.0")
+        Factory.create_dependency("A", {"version": "^1.0", "extras": ["foo"]})
+    )
+    package.add_dependency(Factory.create_dependency("D", "^1.0"))
    installer.update(True)
    installer.whitelist("D")
@@ -1052,16 +1103,20 @@ def test_run_update_with_locked_extras(installer, locker, repo, package):
 def test_run_install_duplicate_dependencies_different_constraints(
    installer, locker, repo, package
 ):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^2.0", "python": ">=4.0"})
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    )
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^2.0", "python": ">=4.0"})
+    )
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
-    package_b10.add_dependency("C", "1.2")
+    package_b10.add_dependency(Factory.create_dependency("C", "1.2"))
-    package_b20.add_dependency("C", "1.5")
+    package_b20.add_dependency(Factory.create_dependency("C", "1.5"))
    package_c12 = get_package("C", "1.2")
    package_c15 = get_package("C", "1.5")
@@ -1159,16 +1214,20 @@ def test_run_install_duplicate_dependencies_different_constraints_with_lock(
            },
        }
    )
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^2.0", "python": ">=4.0"})
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    )
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^2.0", "python": ">=4.0"})
+    )
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
-    package_b10.add_dependency("C", "1.2")
+    package_b10.add_dependency(Factory.create_dependency("C", "1.2"))
-    package_b20.add_dependency("C", "1.5")
+    package_b20.add_dependency(Factory.create_dependency("C", "1.5"))
    package_c12 = get_package("C", "1.2")
    package_c15 = get_package("C", "1.5")
@@ -1226,10 +1285,12 @@ def test_run_update_uninstalls_after_removal_transient_dependency(
            },
        }
    )
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<2.0"})
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<2.0"})
+    )
    package_b10 = get_package("B", "1.0")
@@ -1318,15 +1379,15 @@ def test_run_install_duplicate_dependencies_different_constraints_with_lock_upda
            },
        }
    )
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.1")
-    package_a.add_dependency("B", "^2.0")
+    package_a.add_dependency(Factory.create_dependency("B", "^2.0"))
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
-    package_b10.add_dependency("C", "1.2")
+    package_b10.add_dependency(Factory.create_dependency("C", "1.2"))
-    package_b20.add_dependency("C", "1.5")
+    package_b20.add_dependency(Factory.create_dependency("C", "1.5"))
    package_c12 = get_package("C", "1.2")
    package_c15 = get_package("C", "1.5")
@@ -1359,7 +1420,9 @@ def test_installer_test_solver_finds_compatible_package_for_dependency_python_no
    installer, locker, repo, package, installed
 ):
    package.python_versions = "~2.7 || ^3.4"
-    package.add_dependency("A", {"version": "^1.0", "python": "^3.5"})
+    package.add_dependency(
+        Factory.create_dependency("A", {"version": "^1.0", "python": "^3.5"})
+    )
    package_a101 = get_package("A", "1.0.1")
    package_a101.python_versions = ">=3.6"
@@ -1384,13 +1447,17 @@ def test_installer_test_solver_finds_compatible_package_for_dependency_python_no
 def test_installer_required_extras_should_not_be_removed_when_updating_single_dependency(
    installer, locker, repo, package, installed, env, pool, config
 ):
-    package.add_dependency("A", {"version": "^1.0"})
+    package.add_dependency(Factory.create_dependency("A", {"version": "^1.0"}))
    package_a = get_package("A", "1.0.0")
-    package_a.add_dependency("B", {"version": "^1.0", "extras": ["foo"]})
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "extras": ["foo"]})
+    )
    package_b = get_package("B", "1.0.0")
-    package_b.add_dependency("C", {"version": "^1.0", "optional": True})
+    package_b.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
    package_b.extras = {"foo": [get_dependency("C")]}
    package_c = get_package("C", "1.0.0")
@@ -1408,7 +1475,7 @@ def test_installer_required_extras_should_not_be_removed_when_updating_single_de
    assert 0 == installer.executor.updates_count
    assert 0 == installer.executor.removals_count
-    package.add_dependency("D", "^1.0")
+    package.add_dependency(Factory.create_dependency("D", "^1.0"))
    locker.locked(True)
    locker.mock_lock_data(locker.written_data)
@@ -1457,7 +1524,7 @@ def test_installer_required_extras_should_not_be_removed_when_updating_single_de
    )
    installer.use_executor()
-    package.add_dependency("poetry", {"version": "^0.12.0"})
+    package.add_dependency(Factory.create_dependency("poetry", {"version": "^0.12.0"}))
    installer.update(True)
    installer.run()
@@ -1466,7 +1533,7 @@ def test_installer_required_extras_should_not_be_removed_when_updating_single_de
    assert 0 == installer.executor.updates_count
    assert 0 == installer.executor.removals_count
-    package.add_dependency("pytest", "^3.5")
+    package.add_dependency(Factory.create_dependency("pytest", "^3.5"))
    locker.locked(True)
    locker.mock_lock_data(locker.written_data)
@@ -1514,7 +1581,9 @@ def test_installer_required_extras_should_be_installed(
    installer.use_executor()
    package.add_dependency(
-        "cachecontrol", {"version": "^0.12.5", "extras": ["filecache"]}
+        Factory.create_dependency(
+            "cachecontrol", {"version": "^0.12.5", "extras": ["filecache"]}
+        )
    )
    installer.update(True)
@@ -1585,13 +1654,17 @@ def test_update_multiple_times_with_split_dependencies_is_idempotent(
    )
    package.python_versions = "~2.7 || ^3.4"
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
    a10 = get_package("A", "1.0")
    a11 = get_package("A", "1.1")
-    a11.add_dependency("B", ">=1.0.1")
+    a11.add_dependency(Factory.create_dependency("B", ">=1.0.1"))
-    a11.add_dependency("C", {"version": "^1.0", "python": "~2.7"})
+    a11.add_dependency(
-    a11.add_dependency("C", {"version": "^2.0", "python": "^3.4"})
+        Factory.create_dependency("C", {"version": "^1.0", "python": "~2.7"})
+    )
+    a11.add_dependency(
+        Factory.create_dependency("C", {"version": "^2.0", "python": "^3.4"})
+    )
    b101 = get_package("B", "1.0.1")
    b110 = get_package("B", "1.1.0")
    repo.add_package(a10)
@@ -1626,7 +1699,9 @@ def test_installer_can_install_dependencies_from_forced_source(
    locker, package, installed, env, config
 ):
    package.python_versions = "^3.7"
-    package.add_dependency("tomlkit", {"version": "^0.5", "source": "legacy"})
+    package.add_dependency(
+        Factory.create_dependency("tomlkit", {"version": "^0.5", "source": "legacy"})
+    )
    pool = Pool()
    pool.add_repository(MockLegacyRepository())
@@ -1654,7 +1729,7 @@ def test_installer_can_install_dependencies_from_forced_source(
 def test_run_installs_with_url_file(installer, locker, repo, package):
    url = "https://python-poetry.org/distributions/demo-0.1.0-py2.py3-none-any.whl"
-    package.add_dependency("demo", {"url": url})
+    package.add_dependency(Factory.create_dependency("demo", {"url": url}))
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -1672,11 +1747,13 @@ def test_installer_uses_prereleases_if_they_are_compatible(
 ):
    package.python_versions = "~2.7 || ^3.4"
    package.add_dependency(
-        "prerelease", {"git": "https://github.com/demo/prerelease.git"}
+        Factory.create_dependency(
+            "prerelease", {"git": "https://github.com/demo/prerelease.git"}
+        )
    )
    package_b = get_package("b", "2.0.0")
-    package_b.add_dependency("prerelease", ">=0.19")
+    package_b.add_dependency(Factory.create_dependency("prerelease", ">=0.19"))
    repo.add_package(package_b)
@@ -1686,7 +1763,7 @@ def test_installer_uses_prereleases_if_they_are_compatible(
    locker.locked(True)
    locker.mock_lock_data(locker.written_data)
-    package.add_dependency("b", "^2.0.0")
+    package.add_dependency(Factory.create_dependency("b", "^2.0.0"))
    installer.whitelist(["b"])
    installer.update(True)
@@ -1701,7 +1778,7 @@ def test_installer_can_handle_old_lock_files(
    pool = Pool()
    pool.add_repository(MockRepository())
-    package.add_dependency("pytest", "^3.5", category="dev")
+    package.add_dependency(Factory.create_dependency("pytest", "^3.5", category="dev"))
    locker.locked()
    locker.mock_lock_data(fixture("old-lock"))
@@ -1714,7 +1791,7 @@ def test_installer_can_handle_old_lock_files(
        pool,
        config,
        installed=installed,
-        executor=Executor(MockEnv(), pool, config, NullIO(),),
+        executor=Executor(MockEnv(), pool, config, NullIO()),
    )
    installer.use_executor()

--- a/tests/installation/test_installer_old.py
+++ b/tests/installation/test_installer_old.py
@@ -7,6 +7,7 @@ import pytest
 from clikit.io import NullIO
 from poetry.core.packages import ProjectPackage
+from poetry.factory import Factory
 from poetry.installation import Installer as BaseInstaller
 from poetry.installation.noop_installer import NoopInstaller
 from poetry.packages import Locker as BaseLocker
@@ -42,6 +43,7 @@ class CustomInstalledRepository(InstalledRepository):
 class Locker(BaseLocker):
    def __init__(self):
+        self._lock = TomlFile(Path.cwd().joinpath("poetry.lock"))
        self._written_data = None
        self._locked = False
        self._content_hash = self._get_content_hash()
@@ -50,6 +52,11 @@ class Locker(BaseLocker):
    def written_data(self):
        return self._written_data
+    def set_lock_path(self, lock):
+        self._lock = TomlFile(Path(lock).joinpath("poetry.lock"))
+        return self
    def locked(self, is_locked=True):
        self._locked = is_locked
@@ -145,8 +152,8 @@ def test_run_with_dependencies(installer, locker, repo, package):
    repo.add_package(package_a)
    repo.add_package(package_b)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
    installer.run()
    expected = fixture("with-dependencies")
@@ -208,8 +215,8 @@ def test_run_update_after_removing_dependencies(
    installed.add_package(package_b)
    installed.add_package(package_c)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "~1.1")
+    package.add_dependency(Factory.create_dependency("B", "~1.1"))
    installer.update(True)
    installer.run()
@@ -279,9 +286,9 @@ def test_run_install_no_dev(installer, locker, repo, package, installed):
    installed.add_package(package_b)
    installed.add_package(package_c)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "~1.1")
+    package.add_dependency(Factory.create_dependency("B", "~1.1"))
-    package.add_dependency("C", "~1.2", category="dev")
+    package.add_dependency(Factory.create_dependency("C", "~1.2", category="dev"))
    installer.dev_mode(False)
    installer.run()
@@ -334,7 +341,7 @@ def test_run_install_remove_untracked(installer, locker, repo, package, installe
    installed.add_package(package_pip)  # Always required and never removed.
    installed.add_package(package)  # Root package never removed.
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
    installer.dev_mode(True).remove_untracked(True)
    installer.run()
@@ -379,8 +386,8 @@ def test_run_whitelist_add(installer, locker, repo, package):
    repo.add_package(package_a_new)
    repo.add_package(package_b)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
    installer.update(True)
    installer.whitelist(["B"])
@@ -429,7 +436,7 @@ def test_run_whitelist_remove(installer, locker, repo, package, installed):
    repo.add_package(package_b)
    installed.add_package(package_b)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
    installer.update(True)
    installer.whitelist(["B"])
@@ -453,11 +460,11 @@ def test_add_with_sub_dependencies(installer, locker, repo, package):
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package_a.add_dependency("D", "^1.0")
+    package_a.add_dependency(Factory.create_dependency("D", "^1.0"))
-    package_b.add_dependency("C", "~1.2")
+    package_b.add_dependency(Factory.create_dependency("C", "~1.2"))
    installer.run()
    expected = fixture("with-sub-dependencies")
@@ -480,9 +487,9 @@ def test_run_with_python_versions(installer, locker, repo, package):
    repo.add_package(package_c12)
    repo.add_package(package_c13)
-    package.add_dependency("A", "~1.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", "^1.0")
+    package.add_dependency(Factory.create_dependency("C", "^1.0"))
    installer.run()
    expected = fixture("with-python-versions")
@@ -500,7 +507,7 @@ def test_run_with_optional_and_python_restricted_dependencies(
    package_c12 = get_package("C", "1.2")
    package_c13 = get_package("C", "1.3")
    package_d = get_package("D", "1.4")
-    package_c13.add_dependency("D", "^1.2")
+    package_c13.add_dependency(Factory.create_dependency("D", "^1.2"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -509,9 +516,15 @@ def test_run_with_optional_and_python_restricted_dependencies(
    repo.add_package(package_d)
    package.extras = {"foo": [get_dependency("A", "~1.0")]}
-    package.add_dependency("A", {"version": "~1.0", "optional": True})
+    package.add_dependency(
-    package.add_dependency("B", {"version": "^1.0", "python": "~2.4"})
+        Factory.create_dependency("A", {"version": "~1.0", "optional": True})
-    package.add_dependency("C", {"version": "^1.0", "python": "~2.7 || ^3.4"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "python": "~2.4"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "python": "~2.7 || ^3.4"})
+    )
    installer.run()
    expected = fixture("with-optional-dependencies")
@@ -537,7 +550,7 @@ def test_run_with_optional_and_platform_restricted_dependencies(
    package_c12 = get_package("C", "1.2")
    package_c13 = get_package("C", "1.3")
    package_d = get_package("D", "1.4")
-    package_c13.add_dependency("D", "^1.2")
+    package_c13.add_dependency(Factory.create_dependency("D", "^1.2"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -546,9 +559,15 @@ def test_run_with_optional_and_platform_restricted_dependencies(
    repo.add_package(package_d)
    package.extras = {"foo": [get_dependency("A", "~1.0")]}
-    package.add_dependency("A", {"version": "~1.0", "optional": True})
+    package.add_dependency(
-    package.add_dependency("B", {"version": "^1.0", "platform": "custom"})
+        Factory.create_dependency("A", {"version": "~1.0", "optional": True})
-    package.add_dependency("C", {"version": "^1.0", "platform": "darwin"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "platform": "custom"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "platform": "darwin"})
+    )
    installer.run()
    expected = fixture("with-platform-dependencies")
@@ -570,14 +589,18 @@ def test_run_with_dependencies_extras(installer, locker, repo, package):
    package_c = get_package("C", "1.0")
    package_b.extras = {"foo": [get_dependency("C", "^1.0")]}
-    package_b.add_dependency("C", {"version": "^1.0", "optional": True})
+    package_b.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
    repo.add_package(package_a)
    repo.add_package(package_b)
    repo.add_package(package_c)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", {"version": "^1.0", "extras": ["foo"]})
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "extras": ["foo"]})
+    )
    installer.run()
    expected = fixture("with-dependencies-extras")
@@ -597,10 +620,12 @@ def test_run_does_not_install_extras_if_not_requested(installer, locker, repo, p
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", "^1.0")
+    package.add_dependency(Factory.create_dependency("C", "^1.0"))
-    package.add_dependency("D", {"version": "^1.0", "optional": True})
+    package.add_dependency(
+        Factory.create_dependency("D", {"version": "^1.0", "optional": True})
+    )
    installer.run()
    expected = fixture("extras")
@@ -625,10 +650,12 @@ def test_run_installs_extras_if_requested(installer, locker, repo, package):
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", "^1.0")
+    package.add_dependency(Factory.create_dependency("C", "^1.0"))
-    package.add_dependency("D", {"version": "^1.0", "optional": True})
+    package.add_dependency(
+        Factory.create_dependency("D", {"version": "^1.0", "optional": True})
+    )
    installer.extras(["foo"])
    installer.run()
@@ -654,11 +681,13 @@ def test_run_installs_extras_with_deps_if_requested(installer, locker, repo, pac
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", {"version": "^1.0", "optional": True})
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
-    package_c.add_dependency("D", "^1.0")
+    package_c.add_dependency(Factory.create_dependency("D", "^1.0"))
    installer.extras(["foo"])
    installer.run()
@@ -688,11 +717,13 @@ def test_run_installs_extras_with_deps_if_requested_locked(
    repo.add_package(package_c)
    repo.add_package(package_d)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^1.0")
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
-    package.add_dependency("C", {"version": "^1.0", "optional": True})
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
-    package_c.add_dependency("D", "^1.0")
+    package_c.add_dependency(Factory.create_dependency("D", "^1.0"))
    installer.extras(["foo"])
    installer.run()
@@ -710,7 +741,7 @@ def test_installer_with_pypi_repository(package, locker, installed, config):
        NullIO(), NullEnv(), package, locker, pool, config, installed=installed
    )
-    package.add_dependency("pytest", "^3.5", category="dev")
+    package.add_dependency(Factory.create_dependency("pytest", "^3.5", category="dev"))
    installer.run()
    expected = fixture("with-pypi-repository")
@@ -720,7 +751,7 @@ def test_installer_with_pypi_repository(package, locker, installed, config):
 def test_run_installs_with_local_file(installer, locker, repo, package):
    file_path = fixtures_dir / "distributions/demo-0.1.0-py2.py3-none-any.whl"
-    package.add_dependency("demo", {"file": str(file_path)})
+    package.add_dependency(Factory.create_dependency("demo", {"file": str(file_path)}))
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -737,7 +768,7 @@ def test_run_installs_wheel_with_no_requires_dist(installer, locker, repo, packa
    file_path = (
        fixtures_dir / "wheel_with_no_requires_dist/demo-0.1.0-py2.py3-none-any.whl"
    )
-    package.add_dependency("demo", {"file": str(file_path)})
+    package.add_dependency(Factory.create_dependency("demo", {"file": str(file_path)}))
    installer.run()
@@ -753,7 +784,9 @@ def test_run_installs_with_local_poetry_directory_and_extras(
 ):
    file_path = fixtures_dir / "project_with_extras"
    package.add_dependency(
-        "project-with-extras", {"path": str(file_path), "extras": ["extras_a"]}
+        Factory.create_dependency(
+            "project-with-extras", {"path": str(file_path), "extras": ["extras_a"]}
+        )
    )
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -770,13 +803,16 @@ def test_run_installs_with_local_poetry_directory_and_extras(
 def test_run_installs_with_local_poetry_directory_transitive(
    installer, locker, repo, package, tmpdir
 ):
-    package.root_dir = fixtures_dir.joinpath("directory")
+    root_dir = fixtures_dir.joinpath("directory")
-    directory = fixtures_dir.joinpath("directory").joinpath(
+    package.root_dir = root_dir
-        "project_with_transitive_directory_dependencies"
+    locker.set_lock_path(root_dir)
-    )
+    directory = root_dir.joinpath("project_with_transitive_directory_dependencies")
    package.add_dependency(
-        "project-with-transitive-directory-dependencies",
+        Factory.create_dependency(
-        {"path": str(directory.relative_to(fixtures_dir.joinpath("directory")))},
+            "project-with-transitive-directory-dependencies",
+            {"path": str(directory.relative_to(root_dir))},
+            root_dir=root_dir,
+        )
    )
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -794,13 +830,16 @@ def test_run_installs_with_local_poetry_directory_transitive(
 def test_run_installs_with_local_poetry_file_transitive(
    installer, locker, repo, package, tmpdir
 ):
-    package.root_dir = fixtures_dir.joinpath("directory")
+    root_dir = fixtures_dir.joinpath("directory")
-    directory = fixtures_dir.joinpath("directory").joinpath(
+    package.root_dir = root_dir
-        "project_with_transitive_file_dependencies"
+    locker.set_lock_path(root_dir)
-    )
+    directory = root_dir.joinpath("project_with_transitive_file_dependencies")
    package.add_dependency(
-        "project-with-transitive-file-dependencies",
+        Factory.create_dependency(
-        {"path": str(directory.relative_to(fixtures_dir.joinpath("directory")))},
+            "project-with-transitive-file-dependencies",
+            {"path": str(directory.relative_to(fixtures_dir.joinpath("directory")))},
+            root_dir=root_dir,
+        )
    )
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -819,7 +858,9 @@ def test_run_installs_with_local_setuptools_directory(
    installer, locker, repo, package, tmpdir
 ):
    file_path = fixtures_dir / "project_with_setup/"
-    package.add_dependency("my-package", {"path": str(file_path)})
+    package.add_dependency(
+        Factory.create_dependency("my-package", {"path": str(file_path)})
+    )
    repo.add_package(get_package("pendulum", "1.4.4"))
    repo.add_package(get_package("cachy", "0.2.0"))
@@ -861,8 +902,10 @@ def test_run_with_prereleases(installer, locker, repo, package):
    repo.add_package(package_a)
    repo.add_package(package_b)
-    package.add_dependency("A", {"version": "*", "allow-prereleases": True})
+    package.add_dependency(
-    package.add_dependency("B", "^1.1")
+        Factory.create_dependency("A", {"version": "*", "allow-prereleases": True})
+    )
+    package.add_dependency(Factory.create_dependency("B", "^1.1"))
    installer.update(True)
    installer.whitelist({"B": "^1.1"})
@@ -898,12 +941,16 @@ def test_run_changes_category_if_needed(installer, locker, repo, package):
    )
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.1")
-    package_b.add_dependency("A", "^1.0")
+    package_b.add_dependency(Factory.create_dependency("A", "^1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
-    package.add_dependency("A", {"version": "^1.0", "optional": True}, category="dev")
+    package.add_dependency(
-    package.add_dependency("B", "^1.1")
+        Factory.create_dependency(
+            "A", {"version": "^1.0", "optional": True}, category="dev"
+        )
+    )
+    package.add_dependency(Factory.create_dependency("B", "^1.1"))
    installer.update(True)
    installer.whitelist(["B"])
@@ -941,7 +988,7 @@ def test_run_update_all_with_lock(installer, locker, repo, package):
    repo.add_package(get_package("A", "1.0"))
    repo.add_package(package_a)
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    installer.update(True)
@@ -1008,8 +1055,10 @@ def test_run_update_with_locked_extras(installer, locker, repo, package):
    repo.add_package(get_package("C", "1.1"))
    repo.add_package(get_package("D", "1.1"))
-    package.add_dependency("A", {"version": "^1.0", "extras": ["foo"]})
+    package.add_dependency(
-    package.add_dependency("D", "^1.0")
+        Factory.create_dependency("A", {"version": "^1.0", "extras": ["foo"]})
+    )
+    package.add_dependency(Factory.create_dependency("D", "^1.0"))
    installer.update(True)
    installer.whitelist("D")
@@ -1023,16 +1072,20 @@ def test_run_update_with_locked_extras(installer, locker, repo, package):
 def test_run_install_duplicate_dependencies_different_constraints(
    installer, locker, repo, package
 ):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^2.0", "python": ">=4.0"})
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    )
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^2.0", "python": ">=4.0"})
+    )
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
-    package_b10.add_dependency("C", "1.2")
+    package_b10.add_dependency(Factory.create_dependency("C", "1.2"))
-    package_b20.add_dependency("C", "1.5")
+    package_b20.add_dependency(Factory.create_dependency("C", "1.5"))
    package_c12 = get_package("C", "1.2")
    package_c15 = get_package("C", "1.5")
@@ -1132,16 +1185,20 @@ def test_run_install_duplicate_dependencies_different_constraints_with_lock(
            },
        }
    )
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^2.0", "python": ">=4.0"})
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    )
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^2.0", "python": ">=4.0"})
+    )
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
-    package_b10.add_dependency("C", "1.2")
+    package_b10.add_dependency(Factory.create_dependency("C", "1.2"))
-    package_b20.add_dependency("C", "1.5")
+    package_b20.add_dependency(Factory.create_dependency("C", "1.5"))
    package_c12 = get_package("C", "1.2")
    package_c15 = get_package("C", "1.5")
@@ -1202,10 +1259,12 @@ def test_run_update_uninstalls_after_removal_transient_dependency(
            },
        }
    )
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<2.0"})
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<2.0"})
+    )
    package_b10 = get_package("B", "1.0")
@@ -1297,15 +1356,15 @@ def test_run_install_duplicate_dependencies_different_constraints_with_lock_upda
            },
        }
    )
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.1")
-    package_a.add_dependency("B", "^2.0")
+    package_a.add_dependency(Factory.create_dependency("B", "^2.0"))
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
-    package_b10.add_dependency("C", "1.2")
+    package_b10.add_dependency(Factory.create_dependency("C", "1.2"))
-    package_b20.add_dependency("C", "1.5")
+    package_b20.add_dependency(Factory.create_dependency("C", "1.5"))
    package_c12 = get_package("C", "1.2")
    package_c15 = get_package("C", "1.5")
@@ -1341,7 +1400,9 @@ def test_installer_test_solver_finds_compatible_package_for_dependency_python_no
    installer, locker, repo, package, installed
 ):
    package.python_versions = "~2.7 || ^3.4"
-    package.add_dependency("A", {"version": "^1.0", "python": "^3.5"})
+    package.add_dependency(
+        Factory.create_dependency("A", {"version": "^1.0", "python": "^3.5"})
+    )
    package_a101 = get_package("A", "1.0.1")
    package_a101.python_versions = ">=3.6"
@@ -1368,13 +1429,17 @@ def test_installer_test_solver_finds_compatible_package_for_dependency_python_no
 def test_installer_required_extras_should_not_be_removed_when_updating_single_dependency(
    installer, locker, repo, package, installed, env, pool, config
 ):
-    package.add_dependency("A", {"version": "^1.0"})
+    package.add_dependency(Factory.create_dependency("A", {"version": "^1.0"}))
    package_a = get_package("A", "1.0.0")
-    package_a.add_dependency("B", {"version": "^1.0", "extras": ["foo"]})
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "extras": ["foo"]})
+    )
    package_b = get_package("B", "1.0.0")
-    package_b.add_dependency("C", {"version": "^1.0", "optional": True})
+    package_b.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
    package_b.extras = {"foo": [get_dependency("C")]}
    package_c = get_package("C", "1.0.0")
@@ -1392,7 +1457,7 @@ def test_installer_required_extras_should_not_be_removed_when_updating_single_de
    assert len(installer.installer.updates) == 0
    assert len(installer.installer.removals) == 0
-    package.add_dependency("D", "^1.0")
+    package.add_dependency(Factory.create_dependency("D", "^1.0"))
    locker.locked(True)
    locker.mock_lock_data(locker.written_data)
@@ -1425,7 +1490,7 @@ def test_installer_required_extras_should_not_be_removed_when_updating_single_de
        NullIO(), env, package, locker, pool, config, installed=installed
    )
-    package.add_dependency("poetry", {"version": "^0.12.0"})
+    package.add_dependency(Factory.create_dependency("poetry", {"version": "^0.12.0"}))
    installer.update(True)
    installer.run()
@@ -1434,7 +1499,7 @@ def test_installer_required_extras_should_not_be_removed_when_updating_single_de
    assert len(installer.installer.updates) == 0
    assert len(installer.installer.removals) == 0
-    package.add_dependency("pytest", "^3.5")
+    package.add_dependency(Factory.create_dependency("pytest", "^3.5"))
    locker.locked(True)
    locker.mock_lock_data(locker.written_data)
@@ -1466,7 +1531,9 @@ def test_installer_required_extras_should_be_installed(
    )
    package.add_dependency(
-        "cachecontrol", {"version": "^0.12.5", "extras": ["filecache"]}
+        Factory.create_dependency(
+            "cachecontrol", {"version": "^0.12.5", "extras": ["filecache"]}
+        )
    )
    installer.update(True)
@@ -1529,13 +1596,17 @@ def test_update_multiple_times_with_split_dependencies_is_idempotent(
    )
    package.python_versions = "~2.7 || ^3.4"
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
    a10 = get_package("A", "1.0")
    a11 = get_package("A", "1.1")
-    a11.add_dependency("B", ">=1.0.1")
+    a11.add_dependency(Factory.create_dependency("B", ">=1.0.1"))
-    a11.add_dependency("C", {"version": "^1.0", "python": "~2.7"})
+    a11.add_dependency(
-    a11.add_dependency("C", {"version": "^2.0", "python": "^3.4"})
+        Factory.create_dependency("C", {"version": "^1.0", "python": "~2.7"})
+    )
+    a11.add_dependency(
+        Factory.create_dependency("C", {"version": "^2.0", "python": "^3.4"})
+    )
    b101 = get_package("B", "1.0.1")
    b110 = get_package("B", "1.1.0")
    repo.add_package(a10)
@@ -1570,7 +1641,9 @@ def test_installer_can_install_dependencies_from_forced_source(
    locker, package, installed, env, config
 ):
    package.python_versions = "^3.7"
-    package.add_dependency("tomlkit", {"version": "^0.5", "source": "legacy"})
+    package.add_dependency(
+        Factory.create_dependency("tomlkit", {"version": "^0.5", "source": "legacy"})
+    )
    pool = Pool()
    pool.add_repository(MockLegacyRepository())
@@ -1590,7 +1663,7 @@ def test_installer_can_install_dependencies_from_forced_source(
 def test_run_installs_with_url_file(installer, locker, repo, package):
    url = "https://python-poetry.org/distributions/demo-0.1.0-py2.py3-none-any.whl"
-    package.add_dependency("demo", {"url": url})
+    package.add_dependency(Factory.create_dependency("demo", {"url": url}))
    repo.add_package(get_package("pendulum", "1.4.4"))
@@ -1608,11 +1681,13 @@ def test_installer_uses_prereleases_if_they_are_compatible(
 ):
    package.python_versions = "~2.7 || ^3.4"
    package.add_dependency(
-        "prerelease", {"git": "https://github.com/demo/prerelease.git"}
+        Factory.create_dependency(
+            "prerelease", {"git": "https://github.com/demo/prerelease.git"}
+        )
    )
    package_b = get_package("b", "2.0.0")
-    package_b.add_dependency("prerelease", ">=0.19")
+    package_b.add_dependency(Factory.create_dependency("prerelease", ">=0.19"))
    repo.add_package(package_b)
@@ -1622,7 +1697,7 @@ def test_installer_uses_prereleases_if_they_are_compatible(
    locker.locked(True)
    locker.mock_lock_data(locker.written_data)
-    package.add_dependency("b", "^2.0.0")
+    package.add_dependency(Factory.create_dependency("b", "^2.0.0"))
    installer.whitelist(["b"])
    installer.update(True)
@@ -1637,7 +1712,7 @@ def test_installer_can_handle_old_lock_files(
    pool = Pool()
    pool.add_repository(MockRepository())
-    package.add_dependency("pytest", "^3.5", category="dev")
+    package.add_dependency(Factory.create_dependency("pytest", "^3.5", category="dev"))
    locker.locked()
    locker.mock_lock_data(fixture("old-lock"))

--- a/tests/installation/test_pip_installer.py
+++ b/tests/installation/test_pip_installer.py
@@ -13,10 +13,14 @@ from poetry.utils.env import NullEnv
 @pytest.fixture
 def package_git():
-    package = Package("demo", "1.0.0")
+    package = Package(
-    package.source_type = "git"
+        "demo",
-    package.source_url = "git@github.com:demo/demo.git"
+        "1.0.0",
-    package.source_reference = "master"
+        source_type="git",
+        source_url="git@github.com:demo/demo.git",
+        source_reference="master",
+    )
    return package
@@ -54,9 +58,12 @@ def test_requirement(installer):
 def test_requirement_source_type_url():
    installer = PipInstaller(NullEnv(), NullIO(), Pool())
-    foo = Package("foo", "0.0.0")
+    foo = Package(
-    foo.source_type = "url"
+        "foo",
-    foo.source_url = "https://somehwere.com/releases/foo-1.0.0.tar.gz"
+        "0.0.0",
+        source_type="url",
+        source_url="https://somehwere.com/releases/foo-1.0.0.tar.gz",
+    )
    result = installer.requirement(foo, formatted=True)
    expected = "{}#egg={}".format(foo.source_url, foo.name)
@@ -79,14 +86,20 @@ def test_install_with_non_pypi_default_repository(pool, installer):
    pool.add_repository(default, default=True)
    pool.add_repository(another)
-    foo = Package("foo", "0.0.0")
+    foo = Package(
-    foo.source_type = "legacy"
+        "foo",
-    foo.source_reference = default._name
+        "0.0.0",
-    foo.source_url = default._url
+        source_type="legacy",
-    bar = Package("bar", "0.1.0")
+        source_reference=default.name,
-    bar.source_type = "legacy"
+        source_url=default.url,
-    bar.source_reference = another._name
+    )
-    bar.source_url = another._url
+    bar = Package(
+        "bar",
+        "0.1.0",
+        source_type="legacy",
+        source_reference=another.name,
+        source_url=another.url,
+    )
    installer.install(foo)
    installer.install(bar)
@@ -104,10 +117,13 @@ def test_install_with_cert():
    installer = PipInstaller(null_env, NullIO(), pool)
-    foo = Package("foo", "0.0.0")
+    foo = Package(
-    foo.source_type = "legacy"
+        "foo",
-    foo.source_reference = default._name
+        "0.0.0",
-    foo.source_url = default._url
+        source_type="legacy",
+        source_reference=default.name,
+        source_url=default.url,
+    )
    installer.install(foo)
@@ -133,10 +149,13 @@ def test_install_with_client_cert():
    installer = PipInstaller(null_env, NullIO(), pool)
-    foo = Package("foo", "0.0.0")
+    foo = Package(
-    foo.source_type = "legacy"
+        "foo",
-    foo.source_reference = default._name
+        "0.0.0",
-    foo.source_url = default._url
+        source_type="legacy",
+        source_reference=default.name,
+        source_url=default.url,
+    )
    installer.install(foo)
@@ -161,11 +180,13 @@ def test_uninstall_git_package_nspkg_pth_cleanup(mocker, tmp_venv, pool):
    installer = PipInstaller(tmp_venv, NullIO(), pool)
    # use a namepspace package
-    package = Package("namespace-package-one", "1.0.0")
+    package = Package(
-    package.source_type = "git"
+        "namespace-package-one",
-    package.source_url = "https://github.com/demo/namespace-package-one.git"
+        "1.0.0",
-    package.source_reference = "master"
+        source_type="git",
-    package.develop = True
+        source_url="https://github.com/demo/namespace-package-one.git",
+        source_reference="master",
+    )
    # we do this here because the virtual env might not be usable if failure case is triggered
    pth_file_candidate = tmp_venv.site_packages / "{}-nspkg.pth".format(package.name)

--- a/tests/mixology/helpers.py
+++ b/tests/mixology/helpers.py
 from poetry.core.packages import Package
+from poetry.factory import Factory
 from poetry.mixology.failure import SolveFailure
 from poetry.mixology.version_solver import VersionSolver
 from poetry.packages import DependencyPackage
@@ -11,7 +12,7 @@ def add_to_repo(repository, name, version, deps=None, python=None):
    if deps:
        for dep_name, dep_constraint in deps.items():
-            package.add_dependency(dep_name, dep_constraint)
+            package.add_dependency(Factory.create_dependency(dep_name, dep_constraint))
    repository.add_package(package)

--- a/tests/mixology/version_solver/test_backtracking.py
+++ b/tests/mixology/version_solver/test_backtracking.py
+from poetry.factory import Factory
 from ..helpers import add_to_repo
 from ..helpers import check_solver_result
 def test_circular_dependency_on_older_version(root, provider, repo):
-    root.add_dependency("a", ">=1.0.0")
+    root.add_dependency(Factory.create_dependency("a", ">=1.0.0"))
    add_to_repo(repo, "a", "1.0.0")
    add_to_repo(repo, "a", "2.0.0", deps={"b": "1.0.0"})
@@ -13,8 +15,8 @@ def test_circular_dependency_on_older_version(root, provider, repo):
 def test_diamond_dependency_graph(root, provider, repo):
-    root.add_dependency("a", "*")
+    root.add_dependency(Factory.create_dependency("a", "*"))
-    root.add_dependency("b", "*")
+    root.add_dependency(Factory.create_dependency("b", "*"))
    add_to_repo(repo, "a", "2.0.0", deps={"c": "^1.0.0"})
    add_to_repo(repo, "a", "1.0.0")
@@ -33,8 +35,8 @@ def test_backjumps_after_partial_satisfier(root, provider, repo):
    # c 2.0.0 is incompatible with y 2.0.0 because it requires x 1.0.0, but that
    # requirement only exists because of both a and b. The solver should be able
    # to deduce c 2.0.0's incompatibility and select c 1.0.0 instead.
-    root.add_dependency("c", "*")
+    root.add_dependency(Factory.create_dependency("c", "*"))
-    root.add_dependency("y", "^2.0.0")
+    root.add_dependency(Factory.create_dependency("y", "^2.0.0"))
    add_to_repo(repo, "a", "1.0.0", deps={"x": ">=1.0.0"})
    add_to_repo(repo, "b", "1.0.0", deps={"x": "<2.0.0"})
@@ -56,7 +58,7 @@ def test_rolls_back_leaf_versions_first(root, provider, repo):
    # The latest versions of a and b disagree on c. An older version of either
    # will resolve the problem. This test validates that b, which is farther
    # in the dependency graph from myapp is downgraded first.
-    root.add_dependency("a", "*")
+    root.add_dependency(Factory.create_dependency("a", "*"))
    add_to_repo(repo, "a", "1.0.0", deps={"b": "*"})
    add_to_repo(repo, "a", "2.0.0", deps={"b": "*", "c": "2.0.0"})
@@ -71,7 +73,7 @@ def test_rolls_back_leaf_versions_first(root, provider, repo):
 def test_simple_transitive(root, provider, repo):
    # Only one version of baz, so foo and bar will have to downgrade
    # until they reach it
-    root.add_dependency("foo", "*")
+    root.add_dependency(Factory.create_dependency("foo", "*"))
    add_to_repo(repo, "foo", "1.0.0", deps={"bar": "1.0.0"})
    add_to_repo(repo, "foo", "2.0.0", deps={"bar": "2.0.0"})
@@ -93,8 +95,8 @@ def test_backjump_to_nearer_unsatisfied_package(root, provider, repo):
    # a-2.0.0 whose dependency on c-2.0.0-nonexistent led to the problem. We
    # make sure b has more versions than a so that the solver tries a first
    # since it sorts sibling dependencies by number of versions.
-    root.add_dependency("a", "*")
+    root.add_dependency(Factory.create_dependency("a", "*"))
-    root.add_dependency("b", "*")
+    root.add_dependency(Factory.create_dependency("b", "*"))
    add_to_repo(repo, "a", "1.0.0", deps={"c": "1.0.0"})
    add_to_repo(repo, "a", "2.0.0", deps={"c": "2.0.0-nonexistent"})
@@ -114,8 +116,8 @@ def test_traverse_into_package_with_fewer_versions_first(root, provider, repo):
    # downgraded once). The chosen one depends on which dep is traversed first.
    # Since b has fewer versions, it will be traversed first, which means a will
    # come later. Since later selections are revised first, a gets downgraded.
-    root.add_dependency("a", "*")
+    root.add_dependency(Factory.create_dependency("a", "*"))
-    root.add_dependency("b", "*")
+    root.add_dependency(Factory.create_dependency("b", "*"))
    add_to_repo(repo, "a", "1.0.0", deps={"c": "*"})
    add_to_repo(repo, "a", "2.0.0", deps={"c": "*"})
@@ -133,8 +135,8 @@ def test_traverse_into_package_with_fewer_versions_first(root, provider, repo):
 def test_backjump_past_failed_package_on_disjoint_constraint(root, provider, repo):
-    root.add_dependency("a", "*")
+    root.add_dependency(Factory.create_dependency("a", "*"))
-    root.add_dependency("foo", ">2.0.0")
+    root.add_dependency(Factory.create_dependency("foo", ">2.0.0"))
    add_to_repo(repo, "a", "1.0.0", deps={"foo": "*"})  # ok
    add_to_repo(

--- a/tests/mixology/version_solver/test_basic_graph.py
+++ b/tests/mixology/version_solver/test_basic_graph.py
+from poetry.factory import Factory
 from ..helpers import add_to_repo
 from ..helpers import check_solver_result
 def test_simple_dependencies(root, provider, repo):
-    root.add_dependency("a", "1.0.0")
+    root.add_dependency(Factory.create_dependency("a", "1.0.0"))
-    root.add_dependency("b", "1.0.0")
+    root.add_dependency(Factory.create_dependency("b", "1.0.0"))
    add_to_repo(repo, "a", "1.0.0", deps={"aa": "1.0.0", "ab": "1.0.0"})
    add_to_repo(repo, "b", "1.0.0", deps={"ba": "1.0.0", "bb": "1.0.0"})
@@ -28,8 +30,8 @@ def test_simple_dependencies(root, provider, repo):
 def test_shared_dependencies_with_overlapping_constraints(root, provider, repo):
-    root.add_dependency("a", "1.0.0")
+    root.add_dependency(Factory.create_dependency("a", "1.0.0"))
-    root.add_dependency("b", "1.0.0")
+    root.add_dependency(Factory.create_dependency("b", "1.0.0"))
    add_to_repo(repo, "a", "1.0.0", deps={"shared": ">=2.0.0 <4.0.0"})
    add_to_repo(repo, "b", "1.0.0", deps={"shared": ">=3.0.0 <5.0.0"})
@@ -45,8 +47,8 @@ def test_shared_dependencies_with_overlapping_constraints(root, provider, repo):
 def test_shared_dependency_where_dependent_version_affects_other_dependencies(
    root, provider, repo
 ):
-    root.add_dependency("foo", "<=1.0.2")
+    root.add_dependency(Factory.create_dependency("foo", "<=1.0.2"))
-    root.add_dependency("bar", "1.0.0")
+    root.add_dependency(Factory.create_dependency("bar", "1.0.0"))
    add_to_repo(repo, "foo", "1.0.0")
    add_to_repo(repo, "foo", "1.0.1", deps={"bang": "1.0.0"})
@@ -63,7 +65,7 @@ def test_shared_dependency_where_dependent_version_affects_other_dependencies(
 def test_circular_dependency(root, provider, repo):
-    root.add_dependency("foo", "1.0.0")
+    root.add_dependency(Factory.create_dependency("foo", "1.0.0"))
    add_to_repo(repo, "foo", "1.0.0", deps={"bar": "1.0.0"})
    add_to_repo(repo, "bar", "1.0.0", deps={"foo": "1.0.0"})

--- a/tests/mixology/version_solver/test_python_constraint.py
+++ b/tests/mixology/version_solver/test_python_constraint.py
+from poetry.factory import Factory
 from ..helpers import add_to_repo
 from ..helpers import check_solver_result
 def test_dependency_does_not_match_root_python_constraint(root, provider, repo):
    provider.set_package_python_versions("^3.6")
-    root.add_dependency("foo", "*")
+    root.add_dependency(Factory.create_dependency("foo", "*"))
    add_to_repo(repo, "foo", "1.0.0", python="<3.5")

--- a/tests/mixology/version_solver/test_unsolvable.py
+++ b/tests/mixology/version_solver/test_unsolvable.py
+from poetry.factory import Factory
 from ..helpers import add_to_repo
 from ..helpers import check_solver_result
 def test_no_version_matching_constraint(root, provider, repo):
-    root.add_dependency("foo", "^1.0")
+    root.add_dependency(Factory.create_dependency("foo", "^1.0"))
    add_to_repo(repo, "foo", "2.0.0")
    add_to_repo(repo, "foo", "2.1.3")
@@ -19,8 +21,8 @@ def test_no_version_matching_constraint(root, provider, repo):
 def test_no_version_that_matches_combined_constraints(root, provider, repo):
-    root.add_dependency("foo", "1.0.0")
+    root.add_dependency(Factory.create_dependency("foo", "1.0.0"))
-    root.add_dependency("bar", "1.0.0")
+    root.add_dependency(Factory.create_dependency("bar", "1.0.0"))
    add_to_repo(repo, "foo", "1.0.0", deps={"shared": ">=2.0.0 <3.0.0"})
    add_to_repo(repo, "bar", "1.0.0", deps={"shared": ">=2.9.0 <4.0.0"})
@@ -37,8 +39,8 @@ So, because myapp depends on both foo (1.0.0) and bar (1.0.0), version solving f
 def test_disjoint_constraints(root, provider, repo):
-    root.add_dependency("foo", "1.0.0")
+    root.add_dependency(Factory.create_dependency("foo", "1.0.0"))
-    root.add_dependency("bar", "1.0.0")
+    root.add_dependency(Factory.create_dependency("bar", "1.0.0"))
    add_to_repo(repo, "foo", "1.0.0", deps={"shared": "<=2.0.0"})
    add_to_repo(repo, "bar", "1.0.0", deps={"shared": ">3.0.0"})
@@ -55,8 +57,8 @@ So, because myapp depends on both foo (1.0.0) and bar (1.0.0), version solving f
 def test_disjoint_root_constraints(root, provider, repo):
-    root.add_dependency("foo", "1.0.0")
+    root.add_dependency(Factory.create_dependency("foo", "1.0.0"))
-    root.add_dependency("foo", "2.0.0")
+    root.add_dependency(Factory.create_dependency("foo", "2.0.0"))
    add_to_repo(repo, "foo", "1.0.0")
    add_to_repo(repo, "foo", "2.0.0")
@@ -68,8 +70,8 @@ Because myapp depends on both foo (1.0.0) and foo (2.0.0), version solving faile
 def test_no_valid_solution(root, provider, repo):
-    root.add_dependency("a")
+    root.add_dependency(Factory.create_dependency("a", "*"))
-    root.add_dependency("b")
+    root.add_dependency(Factory.create_dependency("b", "*"))
    add_to_repo(repo, "a", "1.0.0", deps={"b": "1.0.0"})
    add_to_repo(repo, "a", "2.0.0", deps={"b": "2.0.0"})

--- a/tests/mixology/version_solver/test_with_lock.py
+++ b/tests/mixology/version_solver/test_with_lock.py
+from poetry.factory import Factory
 from ...helpers import get_package
 from ..helpers import add_to_repo
 from ..helpers import check_solver_result
 def test_with_compatible_locked_dependencies(root, provider, repo):
-    root.add_dependency("foo", "*")
+    root.add_dependency(Factory.create_dependency("foo", "*"))
    add_to_repo(repo, "foo", "1.0.0", deps={"bar": "1.0.0"})
    add_to_repo(repo, "foo", "1.0.1", deps={"bar": "1.0.1"})
@@ -22,7 +24,7 @@ def test_with_compatible_locked_dependencies(root, provider, repo):
 def test_with_incompatible_locked_dependencies(root, provider, repo):
-    root.add_dependency("foo", ">1.0.1")
+    root.add_dependency(Factory.create_dependency("foo", ">1.0.1"))
    add_to_repo(repo, "foo", "1.0.0", deps={"bar": "1.0.0"})
    add_to_repo(repo, "foo", "1.0.1", deps={"bar": "1.0.1"})
@@ -40,7 +42,7 @@ def test_with_incompatible_locked_dependencies(root, provider, repo):
 def test_with_unrelated_locked_dependencies(root, provider, repo):
-    root.add_dependency("foo", "*")
+    root.add_dependency(Factory.create_dependency("foo", "*"))
    add_to_repo(repo, "foo", "1.0.0", deps={"bar": "1.0.0"})
    add_to_repo(repo, "foo", "1.0.1", deps={"bar": "1.0.1"})
@@ -61,8 +63,8 @@ def test_with_unrelated_locked_dependencies(root, provider, repo):
 def test_unlocks_dependencies_if_necessary_to_ensure_that_a_new_dependency_is_statisfied(
    root, provider, repo
 ):
-    root.add_dependency("foo")
+    root.add_dependency(Factory.create_dependency("foo", "*"))
-    root.add_dependency("newdep", "2.0.0")
+    root.add_dependency(Factory.create_dependency("newdep", "2.0.0"))
    add_to_repo(repo, "foo", "1.0.0", deps={"bar": "<2.0.0"})
    add_to_repo(repo, "bar", "1.0.0", deps={"baz": "<2.0.0"})
@@ -94,8 +96,8 @@ def test_unlocks_dependencies_if_necessary_to_ensure_that_a_new_dependency_is_st
 def test_with_compatible_locked_dependencies_use_latest(root, provider, repo):
-    root.add_dependency("foo", "*")
+    root.add_dependency(Factory.create_dependency("foo", "*"))
-    root.add_dependency("baz", "*")
+    root.add_dependency(Factory.create_dependency("baz", "*"))
    add_to_repo(repo, "foo", "1.0.0", deps={"bar": "1.0.0"})
    add_to_repo(repo, "foo", "1.0.1", deps={"bar": "1.0.1"})

--- a/tests/packages/test_locker.py
+++ b/tests/packages/test_locker.py
@@ -4,8 +4,10 @@ import tempfile
 import pytest
 import tomlkit
+from poetry.core.packages.package import Package
 from poetry.core.packages.project_package import ProjectPackage
 from poetry.core.semver.version import Version
+from poetry.factory import Factory
 from poetry.packages.locker import Locker
 from ..helpers import get_dependency
@@ -28,9 +30,17 @@ def root():
 def test_lock_file_data_is_ordered(locker, root):
    package_a = get_package("A", "1.0.0")
-    package_a.add_dependency("B", "^1.0")
+    package_a.add_dependency(Factory.create_dependency("B", "^1.0"))
    package_a.files = [{"file": "foo", "hash": "456"}, {"file": "bar", "hash": "123"}]
-    packages = [package_a, get_package("B", "1.2")]
+    package_git = Package(
+        "git-package",
+        "1.2.3",
+        source_type="git",
+        source_url="https://github.com/python-poetry/poetry.git",
+        source_reference="develop",
+        source_resolved_reference="123456",
+    )
+    packages = [package_a, get_package("B", "1.2"), package_git]
    locker.set_lock_data(root, packages)
@@ -38,28 +48,42 @@ def test_lock_file_data_is_ordered(locker, root):
        content = f.read()
    expected = """[[package]]
-category = "main"
-description = ""
 name = "A"
+version = "1.0.0"
+description = ""
+category = "main"
 optional = false
 python-versions = "*"
-version = "1.0.0"
 [package.dependencies]
 B = "^1.0"
 [[package]]
+name = "B"
+version = "1.2"
+description = ""
 category = "main"
+optional = false
+python-versions = "*"
+[[package]]
+name = "git-package"
+version = "1.2.3"
 description = ""
-name = "B"
+category = "main"
 optional = false
 python-versions = "*"
-version = "1.2"
+[package.source]
+type = "git"
+url = "https://github.com/python-poetry/poetry.git"
+reference = "develop"
+resolved_reference = "123456"
 [metadata]
-content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 lock-version = "1.1"
 python-versions = "*"
+content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 [metadata.files]
 A = [
@@ -67,6 +91,7 @@ A = [
    {file = "foo", hash = "456"},
 ]
 B = []
+git-package = []
 """
    assert expected == content
@@ -75,12 +100,12 @@ B = []
 def test_locker_properly_loads_extras(locker):
    content = """\
 [[package]]
-category = "main"
-description = "httplib2 caching for requests"
 name = "cachecontrol"
+version = "0.12.5"
+description = "httplib2 caching for requests"
+category = "main"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
-version = "0.12.5"
 [package.dependencies]
 msgpack = "*"
@@ -95,9 +120,9 @@ filecache = ["lockfile (>=0.9)"]
 redis = ["redis (>=2.10.5)"]
 [metadata]
-content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 lock-version = "1.1"
 python-versions = "~2.7 || ^3.4"
+content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 [metadata.files]
 cachecontrol = []
@@ -127,17 +152,17 @@ def test_lock_packages_with_null_description(locker, root):
        content = f.read()
    expected = """[[package]]
-category = "main"
-description = ""
 name = "A"
+version = "1.0.0"
+description = ""
+category = "main"
 optional = false
 python-versions = "*"
-version = "1.0.0"
 [metadata]
-content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 lock-version = "1.1"
 python-versions = "*"
+content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 [metadata.files]
 A = []
@@ -148,36 +173,36 @@ A = []
 def test_lock_file_should_not_have_mixed_types(locker, root):
    package_a = get_package("A", "1.0.0")
-    package_a.add_dependency("B", "^1.0.0")
+    package_a.add_dependency(Factory.create_dependency("B", "^1.0.0"))
-    package_a.add_dependency("B", {"version": ">=1.0.0", "optional": True})
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": ">=1.0.0", "optional": True})
+    )
    package_a.requires[-1].activate()
    package_a.extras["foo"] = [get_dependency("B", ">=1.0.0")]
    locker.set_lock_data(root, [package_a])
    expected = """[[package]]
-category = "main"
-description = ""
 name = "A"
+version = "1.0.0"
+description = ""
+category = "main"
 optional = false
 python-versions = "*"
-version = "1.0.0"
 [package.dependencies]
-[[package.dependencies.B]]
+B = [
-version = "^1.0.0"
+    {version = "^1.0.0"},
+    {version = ">=1.0.0", optional = true},
-[[package.dependencies.B]]
+]
-optional = true
-version = ">=1.0.0"
 [package.extras]
 foo = ["B (>=1.0.0)"]
 [metadata]
-content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 lock-version = "1.1"
 python-versions = "*"
+content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 [metadata.files]
 A = []
@@ -191,12 +216,12 @@ A = []
 def test_reading_lock_file_should_raise_an_error_on_invalid_data(locker):
    content = u"""[[package]]
-category = "main"
-description = ""
 name = "A"
+version = "1.0.0"
+description = ""
+category = "main"
 optional = false
 python-versions = "*"
-version = "1.0.0"
 [package.extras]
 foo = ["bar"]
@@ -205,9 +230,9 @@ foo = ["bar"]
 foo = ["bar"]
 [metadata]
-content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 lock-version = "1.1"
 python-versions = "*"
+content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 [metadata.files]
 A = []
@@ -222,9 +247,13 @@ A = []
 def test_locking_legacy_repository_package_should_include_source_section(root, locker):
-    package_a = get_package("A", "1.0.0")
+    package_a = Package(
-    package_a.source_url = "https://foo.bar"
+        "A",
-    package_a.source_reference = "legacy"
+        "1.0.0",
+        source_type="legacy",
+        source_url="https://foo.bar",
+        source_reference="legacy",
+    )
    packages = [package_a]
    locker.set_lock_data(root, packages)
@@ -233,21 +262,22 @@ def test_locking_legacy_repository_package_should_include_source_section(root, l
        content = f.read()
    expected = """[[package]]
-category = "main"
-description = ""
 name = "A"
+version = "1.0.0"
+description = ""
+category = "main"
 optional = false
 python-versions = "*"
-version = "1.0.0"
 [package.source]
-reference = "legacy"
+type = "legacy"
 url = "https://foo.bar"
+reference = "legacy"
 [metadata]
-content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 lock-version = "1.1"
 python-versions = "*"
+content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 [metadata.files]
 A = []
@@ -261,9 +291,9 @@ def test_locker_should_emit_warnings_if_lock_version_is_newer_but_allowed(
 ):
    content = """\
 [metadata]
-content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 lock-version = "{version}"
 python-versions = "~2.7 || ^3.4"
+content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 [metadata.files]
 """.format(
@@ -293,9 +323,9 @@ def test_locker_should_raise_an_error_if_lock_version_is_newer_and_not_allowed(
 ):
    content = """\
 [metadata]
-content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 lock-version = "2.0"
 python-versions = "~2.7 || ^3.4"
+content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 [metadata.files]
 """
@@ -310,27 +340,29 @@ python-versions = "~2.7 || ^3.4"
 def test_extras_dependencies_are_ordered(locker, root):
    package_a = get_package("A", "1.0.0")
    package_a.add_dependency(
-        "B", {"version": "^1.0.0", "optional": True, "extras": ["c", "a", "b"]}
+        Factory.create_dependency(
+            "B", {"version": "^1.0.0", "optional": True, "extras": ["c", "a", "b"]}
+        )
    )
    package_a.requires[-1].activate()
    locker.set_lock_data(root, [package_a])
    expected = """[[package]]
-category = "main"
-description = ""
 name = "A"
+version = "1.0.0"
+description = ""
+category = "main"
 optional = false
 python-versions = "*"
-version = "1.0.0"
 [package.dependencies]
 B = {version = "^1.0.0", extras = ["a", "b", "c"], optional = true}
 [metadata]
-content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 lock-version = "1.1"
 python-versions = "*"
+content-hash = "115cf985d932e9bf5f540555bbdd75decbb62cac81e399375fc19f6277f8c1d8"
 [metadata.files]
 A = []
@@ -351,9 +383,9 @@ def test_locker_should_neither_emit_warnings_nor_raise_error_for_lower_compatibl
    )
    content = """\
 [metadata]
-content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 lock-version = "{version}"
 python-versions = "~2.7 || ^3.4"
+content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 [metadata.files]
 """.format(

--- a/tests/puzzle/test_provider.py
+++ b/tests/puzzle/test_provider.py
@@ -54,7 +54,11 @@ def test_search_for_vcs_setup_egg_info(provider):
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [get_dependency("pendulum", ">=1.4.4")]
+    required = [r for r in package.requires if not r.is_optional()]
+    optional = [r for r in package.requires if r.is_optional()]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -62,17 +66,19 @@ def test_search_for_vcs_setup_egg_info(provider):
 def test_search_for_vcs_setup_egg_info_with_extras(provider):
-    dependency = VCSDependency("demo", "git", "https://github.com/demo/demo.git")
+    dependency = VCSDependency(
-    dependency.extras.append("foo")
+        "demo", "git", "https://github.com/demo/demo.git", extras=["foo"]
+    )
    package = provider.search_for_vcs(dependency)[0]
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [
-        get_dependency("pendulum", ">=1.4.4"),
+    required = [r for r in package.requires if not r.is_optional()]
-        get_dependency("cleo", optional=True),
+    optional = [r for r in package.requires if r.is_optional()]
-    ]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -89,7 +95,11 @@ def test_search_for_vcs_read_setup(provider, mocker):
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [get_dependency("pendulum", ">=1.4.4")]
+    required = [r for r in package.requires if not r.is_optional()]
+    optional = [r for r in package.requires if r.is_optional()]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -100,21 +110,19 @@ def test_search_for_vcs_read_setup(provider, mocker):
 def test_search_for_vcs_read_setup_with_extras(provider, mocker):
    mocker.patch("poetry.utils.env.EnvManager.get", return_value=MockEnv())
-    dependency = VCSDependency("demo", "git", "https://github.com/demo/demo.git")
+    dependency = VCSDependency(
-    dependency.extras.append("foo")
+        "demo", "git", "https://github.com/demo/demo.git", extras=["foo"]
+    )
    package = provider.search_for_vcs(dependency)[0]
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [
-        get_dependency("pendulum", ">=1.4.4"),
+    required = [r for r in package.requires if not r.is_optional()]
-        get_dependency("cleo", optional=True),
+    optional = [r for r in package.requires if r.is_optional()]
-    ]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
-    assert package.extras == {
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
-        "foo": [get_dependency("cleo")],
-        "bar": [get_dependency("tomlkit")],
-    }
 def test_search_for_vcs_read_setup_raises_error_if_no_version(provider, mocker):
@@ -145,7 +153,11 @@ def test_search_for_directory_setup_egg_info(provider, directory):
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [get_dependency("pendulum", ">=1.4.4")]
+    required = [r for r in package.requires if not r.is_optional()]
+    optional = [r for r in package.requires if r.is_optional()]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -161,17 +173,18 @@ def test_search_for_directory_setup_egg_info_with_extras(provider):
        / "github.com"
        / "demo"
        / "demo",
+        extras=["foo"],
    )
-    dependency.extras.append("foo")
    package = provider.search_for_directory(dependency)[0]
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [
-        get_dependency("pendulum", ">=1.4.4"),
+    required = [r for r in package.requires if not r.is_optional()]
-        get_dependency("cleo", optional=True),
+    optional = [r for r in package.requires if r.is_optional()]
-    ]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -200,7 +213,11 @@ def test_search_for_directory_setup_with_base(provider, directory):
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [get_dependency("pendulum", ">=1.4.4")]
+    required = [r for r in package.requires if not r.is_optional()]
+    optional = [r for r in package.requires if r.is_optional()]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -233,7 +250,11 @@ def test_search_for_directory_setup_read_setup(provider, mocker):
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [get_dependency("pendulum", ">=1.4.4")]
+    required = [r for r in package.requires if not r.is_optional()]
+    optional = [r for r in package.requires if r.is_optional()]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -252,17 +273,18 @@ def test_search_for_directory_setup_read_setup_with_extras(provider, mocker):
        / "github.com"
        / "demo"
        / "demo",
+        extras=["foo"],
    )
-    dependency.extras.append("foo")
    package = provider.search_for_directory(dependency)[0]
    assert package.name == "demo"
    assert package.version.text == "0.1.2"
-    assert package.requires == [
-        get_dependency("pendulum", ">=1.4.4"),
+    required = [r for r in package.requires if not r.is_optional()]
-        get_dependency("cleo", optional=True),
+    optional = [r for r in package.requires if r.is_optional()]
-    ]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [get_dependency("tomlkit"), get_dependency("cleo")]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -299,7 +321,18 @@ def test_search_for_directory_poetry(provider):
    assert package.name == "project-with-extras"
    assert package.version.text == "1.2.3"
-    assert package.requires == []
+    required = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if not r.is_optional()
+    ]
+    optional = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if r.is_optional()
+    ]
+    assert required == []
+    assert optional == [
+        get_dependency("cachy", ">=0.2.0"),
+        get_dependency("pendulum", ">=1.4.4"),
+    ]
    assert package.extras == {
        "extras_a": [get_dependency("pendulum", ">=1.4.4")],
        "extras_b": [get_dependency("cachy", ">=0.2.0")],
@@ -310,14 +343,25 @@ def test_search_for_directory_poetry_with_extras(provider):
    dependency = DirectoryDependency(
        "project-with-extras",
        Path(__file__).parent.parent / "fixtures" / "project_with_extras",
+        extras=["extras_a"],
    )
-    dependency.extras.append("extras_a")
    package = provider.search_for_directory(dependency)[0]
    assert package.name == "project-with-extras"
    assert package.version.text == "1.2.3"
-    assert package.requires == [get_dependency("pendulum", ">=1.4.4")]
+    required = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if not r.is_optional()
+    ]
+    optional = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if r.is_optional()
+    ]
+    assert required == []
+    assert optional == [
+        get_dependency("cachy", ">=0.2.0"),
+        get_dependency("pendulum", ">=1.4.4"),
+    ]
    assert package.extras == {
        "extras_a": [get_dependency("pendulum", ">=1.4.4")],
        "extras_b": [get_dependency("cachy", ">=0.2.0")],
@@ -337,7 +381,18 @@ def test_search_for_file_sdist(provider):
    assert package.name == "demo"
    assert package.version.text == "0.1.0"
-    assert package.requires == [get_dependency("pendulum", ">=1.4.4")]
+    required = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if not r.is_optional()
+    ]
+    optional = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if r.is_optional()
+    ]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [
+        get_dependency("cleo"),
+        get_dependency("tomlkit"),
+    ]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -351,16 +406,24 @@ def test_search_for_file_sdist_with_extras(provider):
        / "fixtures"
        / "distributions"
        / "demo-0.1.0.tar.gz",
+        extras=["foo"],
    )
-    dependency.extras.append("foo")
    package = provider.search_for_file(dependency)[0]
    assert package.name == "demo"
    assert package.version.text == "0.1.0"
-    assert package.requires == [
-        get_dependency("pendulum", ">=1.4.4"),
+    required = [
-        get_dependency("cleo", optional=True),
+        r for r in sorted(package.requires, key=lambda r: r.name) if not r.is_optional()
+    ]
+    optional = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if r.is_optional()
+    ]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [
+        get_dependency("cleo"),
+        get_dependency("tomlkit"),
    ]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
@@ -381,7 +444,18 @@ def test_search_for_file_wheel(provider):
    assert package.name == "demo"
    assert package.version.text == "0.1.0"
-    assert package.requires == [get_dependency("pendulum", ">=1.4.4")]
+    required = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if not r.is_optional()
+    ]
+    optional = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if r.is_optional()
+    ]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [
+        get_dependency("cleo"),
+        get_dependency("tomlkit"),
+    ]
    assert package.extras == {
        "foo": [get_dependency("cleo")],
        "bar": [get_dependency("tomlkit")],
@@ -395,16 +469,24 @@ def test_search_for_file_wheel_with_extras(provider):
        / "fixtures"
        / "distributions"
        / "demo-0.1.0-py2.py3-none-any.whl",
+        extras=["foo"],
    )
-    dependency.extras.append("foo")
    package = provider.search_for_file(dependency)[0]
    assert package.name == "demo"
    assert package.version.text == "0.1.0"
-    assert package.requires == [
-        get_dependency("pendulum", ">=1.4.4"),
+    required = [
-        get_dependency("cleo", optional=True),
+        r for r in sorted(package.requires, key=lambda r: r.name) if not r.is_optional()
+    ]
+    optional = [
+        r for r in sorted(package.requires, key=lambda r: r.name) if r.is_optional()
+    ]
+    assert required == [get_dependency("pendulum", ">=1.4.4")]
+    assert optional == [
+        get_dependency("cleo"),
+        get_dependency("tomlkit"),
    ]
    assert package.extras == {
        "foo": [get_dependency("cleo")],

--- a/tests/puzzle/test_solver.py
+++ b/tests/puzzle/test_solver.py
@@ -2,9 +2,11 @@ import pytest
 from clikit.io import NullIO
+from poetry.core.packages import Package
 from poetry.core.packages import ProjectPackage
 from poetry.core.packages import dependency_from_pep_508
 from poetry.core.version.markers import parse_marker
+from poetry.factory import Factory
 from poetry.puzzle import Solver
 from poetry.puzzle.exceptions import SolverProblemError
 from poetry.puzzle.provider import Provider as BaseProvider
@@ -87,11 +89,11 @@ def check_solver_result(ops, expected):
            result.append({"job": job, "package": op.package, "skipped": op.skipped})
-    assert result == expected
+    assert expected == result
 def test_solver_install_single(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
    repo.add_package(package_a)
@@ -125,7 +127,7 @@ def test_remove_non_installed(solver, repo, locked):
 def test_install_non_existing_package_fail(solver, repo, package):
-    package.add_dependency("B", "1")
+    package.add_dependency(Factory.create_dependency("B", "1"))
    package_a = get_package("A", "1.0")
    repo.add_package(package_a)
@@ -135,7 +137,7 @@ def test_install_non_existing_package_fail(solver, repo, package):
 def test_solver_with_deps(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -159,7 +161,7 @@ def test_solver_with_deps(solver, repo, package):
 def test_install_honours_not_equal(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -187,9 +189,9 @@ def test_install_honours_not_equal(solver, repo, package):
 def test_install_with_deps_in_order(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
-    package.add_dependency("C")
+    package.add_dependency(Factory.create_dependency("C", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -216,7 +218,7 @@ def test_install_with_deps_in_order(solver, repo, package):
 def test_install_installed(solver, repo, installed, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
    installed.add_package(package_a)
@@ -230,7 +232,7 @@ def test_install_installed(solver, repo, installed, package):
 def test_update_installed(solver, repo, installed, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    installed.add_package(get_package("A", "1.0"))
@@ -247,8 +249,8 @@ def test_update_installed(solver, repo, installed, package):
 def test_update_with_use_latest(solver, repo, installed, package, locked):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
    installed.add_package(get_package("A", "1.0"))
@@ -276,13 +278,13 @@ def test_update_with_use_latest(solver, repo, installed, package, locked):
 def test_solver_sets_categories(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B", category="dev")
+    package.add_dependency(Factory.create_dependency("B", "*", category="dev"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
    package_c = get_package("C", "1.0")
-    package_b.add_dependency("C", "~1.0")
+    package_b.add_dependency(Factory.create_dependency("C", "~1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -306,8 +308,8 @@ def test_solver_sets_categories(solver, repo, package):
 def test_solver_respects_root_package_python_versions(solver, repo, package):
    solver.provider.set_package_python_versions("~3.4")
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -316,7 +318,7 @@ def test_solver_respects_root_package_python_versions(solver, repo, package):
    package_c.python_versions = "^3.4"
    package_c11 = get_package("C", "1.1")
    package_c11.python_versions = "^3.6"
-    package_b.add_dependency("C", "^1.0")
+    package_b.add_dependency(Factory.create_dependency("C", "^1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -337,15 +339,15 @@ def test_solver_respects_root_package_python_versions(solver, repo, package):
 def test_solver_fails_if_mismatch_root_python_versions(solver, repo, package):
    solver.provider.set_package_python_versions("^3.4")
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
    package_b.python_versions = "^3.6"
    package_c = get_package("C", "1.0")
    package_c.python_versions = "~3.3"
-    package_b.add_dependency("C", "~1.0")
+    package_b.add_dependency(Factory.create_dependency("C", "~1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -358,15 +360,19 @@ def test_solver_fails_if_mismatch_root_python_versions(solver, repo, package):
 def test_solver_solves_optional_and_compatible_packages(solver, repo, package):
    solver.provider.set_package_python_versions("~3.4")
    package.extras["foo"] = [get_dependency("B")]
-    package.add_dependency("A", {"version": "*", "python": "^3.4"})
+    package.add_dependency(
-    package.add_dependency("B", {"version": "*", "optional": True})
+        Factory.create_dependency("A", {"version": "*", "python": "^3.4"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "*", "optional": True})
+    )
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
    package_b.python_versions = "^3.3"
    package_c = get_package("C", "1.0")
    package_c.python_versions = "^3.4"
-    package_b.add_dependency("C", "^1.0")
+    package_b.add_dependency(Factory.create_dependency("C", "^1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -385,8 +391,8 @@ def test_solver_solves_optional_and_compatible_packages(solver, repo, package):
 def test_solver_does_not_return_extras_if_not_requested(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -410,8 +416,10 @@ def test_solver_does_not_return_extras_if_not_requested(solver, repo, package):
 def test_solver_returns_extras_if_requested(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B", {"version": "*", "extras": ["foo"]})
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "*", "extras": ["foo"]})
+    )
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -442,9 +450,11 @@ def test_solver_returns_extras_if_requested(solver, repo, package):
 def test_solver_returns_prereleases_if_requested(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
-    package.add_dependency("C", {"version": "*", "allow-prereleases": True})
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "*", "allow-prereleases": True})
+    )
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -469,9 +479,9 @@ def test_solver_returns_prereleases_if_requested(solver, repo, package):
 def test_solver_does_not_return_prereleases_if_not_requested(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
-    package.add_dependency("C")
+    package.add_dependency(Factory.create_dependency("C", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -496,17 +506,19 @@ def test_solver_does_not_return_prereleases_if_not_requested(solver, repo, packa
 def test_solver_sub_dependencies_with_requirements(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
    package_c = get_package("C", "1.0")
    package_d = get_package("D", "1.0")
-    package_c.add_dependency("D", {"version": "^1.0", "python": "<4.0"})
+    package_c.add_dependency(
-    package_a.add_dependency("C")
+        Factory.create_dependency("D", {"version": "^1.0", "python": "<4.0"})
-    package_b.add_dependency("D", "^1.0")
+    )
+    package_a.add_dependency(Factory.create_dependency("C", "*"))
+    package_b.add_dependency(Factory.create_dependency("D", "^1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -530,9 +542,15 @@ def test_solver_sub_dependencies_with_requirements(solver, repo, package):
 def test_solver_sub_dependencies_with_requirements_complex(solver, repo, package):
-    package.add_dependency("A", {"version": "^1.0", "python": "<5.0"})
+    package.add_dependency(
-    package.add_dependency("B", {"version": "^1.0", "python": "<5.0"})
+        Factory.create_dependency("A", {"version": "^1.0", "python": "<5.0"})
-    package.add_dependency("C", {"version": "^1.0", "python": "<4.0"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<5.0"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "python": "<4.0"})
+    )
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
@@ -541,12 +559,22 @@ def test_solver_sub_dependencies_with_requirements_complex(solver, repo, package
    package_e = get_package("E", "1.0")
    package_f = get_package("F", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<4.0"})
+    package_a.add_dependency(
-    package_a.add_dependency("D", {"version": "^1.0", "python": "<4.0"})
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<4.0"})
-    package_b.add_dependency("E", {"version": "^1.0", "platform": "win32"})
+    )
-    package_b.add_dependency("F", {"version": "^1.0", "python": "<5.0"})
+    package_a.add_dependency(
-    package_c.add_dependency("F", {"version": "^1.0", "python": "<4.0"})
+        Factory.create_dependency("D", {"version": "^1.0", "python": "<4.0"})
-    package_d.add_dependency("F")
+    )
+    package_b.add_dependency(
+        Factory.create_dependency("E", {"version": "^1.0", "platform": "win32"})
+    )
+    package_b.add_dependency(
+        Factory.create_dependency("F", {"version": "^1.0", "python": "<5.0"})
+    )
+    package_c.add_dependency(
+        Factory.create_dependency("F", {"version": "^1.0", "python": "<4.0"})
+    )
+    package_d.add_dependency(Factory.create_dependency("F", "*"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -574,13 +602,15 @@ def test_solver_sub_dependencies_with_not_supported_python_version(
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("^3.5")
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
    package_b.python_versions = "<2.0"
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<2.0"})
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<2.0"})
+    )
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -594,18 +624,24 @@ def test_solver_with_dependency_in_both_main_and_dev_dependencies(
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("^3.5")
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("A", {"version": "*", "extras": ["foo"]}, category="dev")
+    package.add_dependency(
+        Factory.create_dependency(
+            "A", {"version": "*", "extras": ["foo"]}, category="dev"
+        )
+    )
    package_a = get_package("A", "1.0")
    package_a.extras["foo"] = [get_dependency("C")]
-    package_a.add_dependency("C", {"version": "^1.0", "optional": True})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^1.0"})
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
+    package_a.add_dependency(Factory.create_dependency("B", {"version": "^1.0"}))
    package_b = get_package("B", "1.0")
    package_c = get_package("C", "1.0")
-    package_c.add_dependency("D", "^1.0")
+    package_c.add_dependency(Factory.create_dependency("D", "^1.0"))
    package_d = get_package("D", "1.0")
@@ -640,24 +676,30 @@ def test_solver_with_dependency_in_both_main_and_dev_dependencies(
 def test_solver_with_dependency_in_both_main_and_dev_dependencies_with_one_more_dependent(
    solver, repo, package
 ):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("E")
+    package.add_dependency(Factory.create_dependency("E", "*"))
-    package.add_dependency("A", {"version": "*", "extras": ["foo"]}, category="dev")
+    package.add_dependency(
+        Factory.create_dependency(
+            "A", {"version": "*", "extras": ["foo"]}, category="dev"
+        )
+    )
    package_a = get_package("A", "1.0")
    package_a.extras["foo"] = [get_dependency("C")]
-    package_a.add_dependency("C", {"version": "^1.0", "optional": True})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^1.0"})
+        Factory.create_dependency("C", {"version": "^1.0", "optional": True})
+    )
+    package_a.add_dependency(Factory.create_dependency("B", {"version": "^1.0"}))
    package_b = get_package("B", "1.0")
    package_c = get_package("C", "1.0")
-    package_c.add_dependency("D", "^1.0")
+    package_c.add_dependency(Factory.create_dependency("D", "^1.0"))
    package_d = get_package("D", "1.0")
    package_e = get_package("E", "1.0")
-    package_e.add_dependency("A", "^1.0")
+    package_e.add_dependency(Factory.create_dependency("A", "^1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -692,10 +734,10 @@ def test_solver_with_dependency_in_both_main_and_dev_dependencies_with_one_more_
 def test_solver_with_dependency_and_prerelease_sub_dependencies(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", ">=1.0.0.dev2")
+    package_a.add_dependency(Factory.create_dependency("B", ">=1.0.0.dev2"))
    repo.add_package(package_a)
    repo.add_package(get_package("B", "0.9.0"))
@@ -717,14 +759,14 @@ def test_solver_with_dependency_and_prerelease_sub_dependencies(solver, repo, pa
 def test_solver_circular_dependency(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", "^1.0")
+    package_a.add_dependency(Factory.create_dependency("B", "^1.0"))
    package_b = get_package("B", "1.0")
-    package_b.add_dependency("A", "^1.0")
+    package_b.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package_b.add_dependency("C", "^1.0")
+    package_b.add_dependency(Factory.create_dependency("C", "^1.0"))
    package_c = get_package("C", "1.0")
@@ -747,19 +789,19 @@ def test_solver_circular_dependency(solver, repo, package):
 def test_solver_circular_dependency_chain(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", "^1.0")
+    package_a.add_dependency(Factory.create_dependency("B", "^1.0"))
    package_b = get_package("B", "1.0")
-    package_b.add_dependency("C", "^1.0")
+    package_b.add_dependency(Factory.create_dependency("C", "^1.0"))
    package_c = get_package("C", "1.0")
-    package_c.add_dependency("D", "^1.0")
+    package_c.add_dependency(Factory.create_dependency("D", "^1.0"))
    package_d = get_package("D", "1.0")
-    package_d.add_dependency("B", "^1.0")
+    package_d.add_dependency(Factory.create_dependency("B", "^1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -791,9 +833,9 @@ def test_solver_dense_dependencies(solver, repo, package):
        package_ai = get_package("a" + str(i), "1.0")
        repo.add_package(package_ai)
        packages.append(package_ai)
-        package.add_dependency("a" + str(i), "^1.0")
+        package.add_dependency(Factory.create_dependency("a" + str(i), "^1.0"))
        for j in range(i):
-            package_ai.add_dependency("a" + str(j), "^1.0")
+            package_ai.add_dependency(Factory.create_dependency("a" + str(j), "^1.0"))
    ops = solver.solve()
@@ -803,11 +845,15 @@ def test_solver_dense_dependencies(solver, repo, package):
 def test_solver_duplicate_dependencies_same_constraint(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "2.7"})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^1.0", "python": ">=3.4"})
+        Factory.create_dependency("B", {"version": "^1.0", "python": "2.7"})
+    )
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "python": ">=3.4"})
+    )
    package_b = get_package("B", "1.0")
@@ -826,11 +872,15 @@ def test_solver_duplicate_dependencies_same_constraint(solver, repo, package):
 def test_solver_duplicate_dependencies_different_constraints(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<3.4"})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^2.0", "python": ">=3.4"})
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<3.4"})
+    )
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^2.0", "python": ">=3.4"})
+    )
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
@@ -854,11 +904,11 @@ def test_solver_duplicate_dependencies_different_constraints(solver, repo, packa
 def test_solver_duplicate_dependencies_different_constraints_same_requirements(
    solver, repo, package
 ):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0"})
+    package_a.add_dependency(Factory.create_dependency("B", {"version": "^1.0"}))
-    package_a.add_dependency("B", {"version": "^2.0"})
+    package_a.add_dependency(Factory.create_dependency("B", {"version": "^2.0"}))
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
@@ -879,16 +929,20 @@ So, because no versions of a match !=1.0
 def test_solver_duplicate_dependencies_sub_dependencies(solver, repo, package):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", {"version": "^1.0", "python": "<3.4"})
+    package_a.add_dependency(
-    package_a.add_dependency("B", {"version": "^2.0", "python": ">=3.4"})
+        Factory.create_dependency("B", {"version": "^1.0", "python": "<3.4"})
+    )
+    package_a.add_dependency(
+        Factory.create_dependency("B", {"version": "^2.0", "python": ">=3.4"})
+    )
    package_b10 = get_package("B", "1.0")
    package_b20 = get_package("B", "2.0")
-    package_b10.add_dependency("C", "1.2")
+    package_b10.add_dependency(Factory.create_dependency("C", "1.2"))
-    package_b20.add_dependency("C", "1.5")
+    package_b20.add_dependency(Factory.create_dependency("C", "1.5"))
    package_c12 = get_package("C", "1.2")
    package_c15 = get_package("C", "1.5")
@@ -914,7 +968,11 @@ def test_solver_duplicate_dependencies_sub_dependencies(solver, repo, package):
 def test_solver_fails_if_dependency_name_does_not_match_package(solver, repo, package):
-    package.add_dependency("my-demo", {"git": "https://github.com/demo/demo.git"})
+    package.add_dependency(
+        Factory.create_dependency(
+            "my-demo", {"git": "https://github.com/demo/demo.git"}
+        )
+    )
    with pytest.raises(RuntimeError):
        solver.solve()
@@ -924,17 +982,17 @@ def test_solver_does_not_get_stuck_in_recursion_on_circular_dependency(
    solver, repo, package
 ):
    package_a = get_package("A", "1.0")
-    package_a.add_dependency("B", "^1.0")
+    package_a.add_dependency(Factory.create_dependency("B", "^1.0"))
    package_b = get_package("B", "1.0")
-    package_b.add_dependency("C", "^1.0")
+    package_b.add_dependency(Factory.create_dependency("C", "^1.0"))
    package_c = get_package("C", "1.0")
-    package_c.add_dependency("B", "^1.0")
+    package_c.add_dependency(Factory.create_dependency("B", "^1.0"))
    repo.add_package(package_a)
    repo.add_package(package_b)
    repo.add_package(package_c)
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
    ops = solver.solve()
@@ -954,14 +1012,20 @@ def test_solver_can_resolve_git_dependencies(solver, repo, package):
    repo.add_package(pendulum)
    repo.add_package(cleo)
-    package.add_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    package.add_dependency(
+        Factory.create_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    )
    ops = solver.solve()
-    demo = get_package("demo", "0.1.2")
+    demo = Package(
-    demo.source_type = "git"
+        "demo",
-    demo.source_url = "https://github.com/demo/demo.git"
+        "0.1.2",
-    demo.source_reference = "9cf87a285a2d3fbb0b9fa621997b3acc3631ed24"
+        source_type="git",
+        source_url="https://github.com/demo/demo.git",
+        source_reference="master",
+        source_resolved_reference="9cf87a285a2d3fbb0b9fa621997b3acc3631ed24",
+    )
    check_solver_result(
        ops,
@@ -971,7 +1035,8 @@ def test_solver_can_resolve_git_dependencies(solver, repo, package):
    op = ops[1]
    assert op.package.source_type == "git"
-    assert op.package.source_reference.startswith("9cf87a2")
+    assert op.package.source_reference == "master"
+    assert op.package.source_resolved_reference.startswith("9cf87a2")
 def test_solver_can_resolve_git_dependencies_with_extras(solver, repo, package):
@@ -981,15 +1046,21 @@ def test_solver_can_resolve_git_dependencies_with_extras(solver, repo, package):
    repo.add_package(cleo)
    package.add_dependency(
-        "demo", {"git": "https://github.com/demo/demo.git", "extras": ["foo"]}
+        Factory.create_dependency(
+            "demo", {"git": "https://github.com/demo/demo.git", "extras": ["foo"]}
+        )
    )
    ops = solver.solve()
-    demo = get_package("demo", "0.1.2")
+    demo = Package(
-    demo.source_type = "git"
+        "demo",
-    demo.source_url = "https://github.com/demo/demo.git"
+        "0.1.2",
-    demo.source_reference = "9cf87a285a2d3fbb0b9fa621997b3acc3631ed24"
+        source_type="git",
+        source_url="https://github.com/demo/demo.git",
+        source_reference="master",
+        source_resolved_reference="9cf87a285a2d3fbb0b9fa621997b3acc3631ed24",
+    )
    check_solver_result(
        ops,
@@ -1012,14 +1083,18 @@ def test_solver_can_resolve_git_dependencies_with_ref(solver, repo, package, ref
    repo.add_package(pendulum)
    repo.add_package(cleo)
-    demo = get_package("demo", "0.1.2")
+    demo = Package(
-    demo.source_type = "git"
+        "demo",
-    demo.source_url = "https://github.com/demo/demo.git"
+        "0.1.2",
-    demo.source_reference = "9cf87a285a2d3fbb0b9fa621997b3acc3631ed24"
+        source_type="git",
+        source_url="https://github.com/demo/demo.git",
+        source_reference=ref[list(ref.keys())[0]],
+        source_resolved_reference="9cf87a285a2d3fbb0b9fa621997b3acc3631ed24",
+    )
    git_config = {demo.source_type: demo.source_url}
    git_config.update(ref)
-    package.add_dependency("demo", git_config)
+    package.add_dependency(Factory.create_dependency("demo", git_config))
    ops = solver.solve()
@@ -1031,14 +1106,17 @@ def test_solver_can_resolve_git_dependencies_with_ref(solver, repo, package, ref
    op = ops[1]
    assert op.package.source_type == "git"
-    assert op.package.source_reference.startswith("9cf87a2")
+    assert op.package.source_reference == ref[list(ref.keys())[0]]
+    assert op.package.source_resolved_reference.startswith("9cf87a2")
 def test_solver_does_not_trigger_conflict_for_python_constraint_if_python_requirement_is_compatible(
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.4")
-    package.add_dependency("A", {"version": "^1.0", "python": "^3.6"})
+    package.add_dependency(
+        Factory.create_dependency("A", {"version": "^1.0", "python": "^3.6"})
+    )
    package_a = get_package("A", "1.0.0")
    package_a.python_versions = ">=3.6"
@@ -1054,12 +1132,16 @@ def test_solver_does_not_trigger_conflict_for_python_constraint_if_python_requir
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.4")
-    package.add_dependency("A", {"version": "^1.0", "python": "^3.6"})
+    package.add_dependency(
-    package.add_dependency("B", {"version": "^1.0", "python": "^3.5.3"})
+        Factory.create_dependency("A", {"version": "^1.0", "python": "^3.6"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("B", {"version": "^1.0", "python": "^3.5.3"})
+    )
    package_a = get_package("A", "1.0.0")
    package_a.python_versions = ">=3.6"
-    package_a.add_dependency("B", "^1.0")
+    package_a.add_dependency(Factory.create_dependency("B", "^1.0"))
    package_b = get_package("B", "1.0.0")
    package_b.python_versions = ">=3.5.3"
@@ -1082,7 +1164,9 @@ def test_solver_triggers_conflict_for_dependency_python_not_fully_compatible_wit
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.4")
-    package.add_dependency("A", {"version": "^1.0", "python": "^3.5"})
+    package.add_dependency(
+        Factory.create_dependency("A", {"version": "^1.0", "python": "^3.5"})
+    )
    package_a = get_package("A", "1.0.0")
    package_a.python_versions = ">=3.6"
@@ -1097,7 +1181,9 @@ def test_solver_finds_compatible_package_for_dependency_python_not_fully_compati
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.4")
-    package.add_dependency("A", {"version": "^1.0", "python": "^3.5"})
+    package.add_dependency(
+        Factory.create_dependency("A", {"version": "^1.0", "python": "^3.5"})
+    )
    package_a101 = get_package("A", "1.0.1")
    package_a101.python_versions = ">=3.6"
@@ -1121,7 +1207,9 @@ def test_solver_does_not_trigger_new_resolution_on_duplicate_dependencies_if_onl
    dep2 = dependency_from_pep_508('B (>=2.0); extra == "bar"')
    dep2.activate()
-    package.add_dependency("A", {"version": "^1.0", "extras": ["foo", "bar"]})
+    package.add_dependency(
+        Factory.create_dependency("A", {"version": "^1.0", "extras": ["foo", "bar"]})
+    )
    package_a = get_package("A", "1.0.0")
    package_a.extras = {"foo": [dep1], "bar": [dep2]}
@@ -1153,8 +1241,10 @@ def test_solver_does_not_raise_conflict_for_locked_conditional_dependencies(
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.4")
-    package.add_dependency("A", {"version": "^1.0", "python": "^3.6"})
+    package.add_dependency(
-    package.add_dependency("B", "^1.0")
+        Factory.create_dependency("A", {"version": "^1.0", "python": "^3.6"})
+    )
+    package.add_dependency(Factory.create_dependency("B", "^1.0"))
    package_a = get_package("A", "1.0.0")
    package_a.python_versions = ">=3.6"
@@ -1182,19 +1272,23 @@ def test_solver_does_not_raise_conflict_for_locked_conditional_dependencies(
 def test_solver_returns_extras_if_requested_in_dependencies_and_not_in_root_package(
    solver, repo, package
 ):
-    package.add_dependency("A")
+    package.add_dependency(Factory.create_dependency("A", "*"))
-    package.add_dependency("B")
+    package.add_dependency(Factory.create_dependency("B", "*"))
-    package.add_dependency("C")
+    package.add_dependency(Factory.create_dependency("C", "*"))
    package_a = get_package("A", "1.0")
    package_b = get_package("B", "1.0")
    package_c = get_package("C", "1.0")
    package_d = get_package("D", "1.0")
-    package_b.add_dependency("C", {"version": "^1.0", "extras": ["foo"]})
+    package_b.add_dependency(
+        Factory.create_dependency("C", {"version": "^1.0", "extras": ["foo"]})
+    )
-    package_c.add_dependency("D", {"version": "^1.0", "optional": True})
+    package_c.add_dependency(
-    package_c.extras = {"foo": [get_dependency("D", "^1.0")]}
+        Factory.create_dependency("D", {"version": "^1.0", "optional": True})
+    )
+    package_c.extras = {"foo": [Factory.create_dependency("D", "^1.0")]}
    repo.add_package(package_a)
    repo.add_package(package_b)
@@ -1217,13 +1311,13 @@ def test_solver_returns_extras_if_requested_in_dependencies_and_not_in_root_pack
 def test_solver_should_not_resolve_prerelease_version_if_not_requested(
    solver, repo, package
 ):
-    package.add_dependency("A", "~1.8.0")
+    package.add_dependency(Factory.create_dependency("A", "~1.8.0"))
-    package.add_dependency("B", "^0.5.0")
+    package.add_dependency(Factory.create_dependency("B", "^0.5.0"))
    package_a185 = get_package("A", "1.8.5")
    package_a19b1 = get_package("A", "1.9b1")
    package_b = get_package("B", "0.5.0")
-    package_b.add_dependency("A", ">=1.9b1")
+    package_b.add_dependency(Factory.create_dependency("A", ">=1.9b1"))
    repo.add_package(package_a185)
    repo.add_package(package_a19b1)
@@ -1237,8 +1331,8 @@ def test_solver_ignores_dependencies_with_incompatible_python_full_version_marke
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("^3.6")
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
-    package.add_dependency("B", "^2.0")
+    package.add_dependency(Factory.create_dependency("B", "^2.0"))
    package_a = get_package("A", "1.0.0")
    package_a.requires.append(
@@ -1271,21 +1365,30 @@ def test_solver_git_dependencies_update(solver, repo, package, installed):
    repo.add_package(pendulum)
    repo.add_package(cleo)
-    demo_installed = get_package("demo", "0.1.2")
+    demo_installed = Package(
-    demo_installed.source_type = "git"
+        "demo",
-    demo_installed.source_url = "https://github.com/demo/demo.git"
+        "0.1.2",
-    demo_installed.source_reference = "123456"
+        source_type="git",
+        source_url="https://github.com/demo/demo.git",
+        source_reference="master",
+        source_resolved_reference="123456",
+    )
+    demo = Package(
+        "demo",
+        "0.1.2",
+        source_type="git",
+        source_url="https://github.com/demo/demo.git",
+        source_reference="master",
+        source_resolved_reference="9cf87a285a2d3fbb0b9fa621997b3acc3631ed24",
+    )
    installed.add_package(demo_installed)
-    package.add_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    package.add_dependency(
+        Factory.create_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    )
    ops = solver.solve()
-    demo = get_package("demo", "0.1.2")
-    demo.source_type = "git"
-    demo.source_url = "https://github.com/demo/demo.git"
-    demo.source_reference = "9cf87a285a2d3fbb0b9fa621997b3acc3631ed24"
    check_solver_result(
        ops,
        [
@@ -1298,8 +1401,9 @@ def test_solver_git_dependencies_update(solver, repo, package, installed):
    assert op.job_type == "update"
    assert op.package.source_type == "git"
-    assert op.package.source_reference.startswith("9cf87a2")
+    assert op.package.source_reference == "master"
-    assert op.initial_package.source_reference == "123456"
+    assert op.package.source_resolved_reference.startswith("9cf87a2")
+    assert op.initial_package.source_resolved_reference == "123456"
 def test_solver_git_dependencies_update_skipped(solver, repo, package, installed):
@@ -1308,13 +1412,19 @@ def test_solver_git_dependencies_update_skipped(solver, repo, package, installed
    repo.add_package(pendulum)
    repo.add_package(cleo)
-    demo = get_package("demo", "0.1.2")
+    demo = Package(
-    demo.source_type = "git"
+        "demo",
-    demo.source_url = "https://github.com/demo/demo.git"
+        "0.1.2",
-    demo.source_reference = "9cf87a285a2d3fbb0b9fa621997b3acc3631ed24"
+        source_type="git",
+        source_url="https://github.com/demo/demo.git",
+        source_reference="master",
+        source_resolved_reference="9cf87a285a2d3fbb0b9fa621997b3acc3631ed24",
+    )
    installed.add_package(demo)
-    package.add_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    package.add_dependency(
+        Factory.create_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    )
    ops = solver.solve()
@@ -1335,14 +1445,20 @@ def test_solver_git_dependencies_short_hash_update_skipped(
    repo.add_package(pendulum)
    repo.add_package(cleo)
-    demo = get_package("demo", "0.1.2")
+    demo = Package(
-    demo.source_type = "git"
+        "demo",
-    demo.source_url = "https://github.com/demo/demo.git"
+        "0.1.2",
-    demo.source_reference = "9cf87a285a2d3fbb0b9fa621997b3acc3631ed24"
+        source_type="git",
+        source_url="https://github.com/demo/demo.git",
+        source_reference="master",
+        source_resolved_reference="9cf87a285a2d3fbb0b9fa621997b3acc3631ed24",
+    )
    installed.add_package(demo)
    package.add_dependency(
-        "demo", {"git": "https://github.com/demo/demo.git", "rev": "9cf87a2"}
+        Factory.create_dependency(
+            "demo", {"git": "https://github.com/demo/demo.git", "rev": "9cf87a2"}
+        )
    )
    ops = solver.solve()
@@ -1351,7 +1467,18 @@ def test_solver_git_dependencies_short_hash_update_skipped(
        ops,
        [
            {"job": "install", "package": pendulum},
-            {"job": "install", "package": demo, "skipped": True},
+            {
+                "job": "install",
+                "package": Package(
+                    "demo",
+                    "0.1.2",
+                    source_type="git",
+                    source_url="https://github.com/demo/demo.git",
+                    source_reference="9cf87a285a2d3fbb0b9fa621997b3acc3631ed24",
+                    source_resolved_reference="9cf87a285a2d3fbb0b9fa621997b3acc3631ed24",
+                ),
+                "skipped": True,
+            },
        ],
    )
@@ -1369,13 +1496,11 @@ def test_solver_can_resolve_directory_dependencies(solver, repo, package):
        / "demo"
    ).as_posix()
-    package.add_dependency("demo", {"path": path})
+    package.add_dependency(Factory.create_dependency("demo", {"path": path}))
    ops = solver.solve()
-    demo = get_package("demo", "0.1.2")
+    demo = Package("demo", "0.1.2", source_type="directory", source_url=path)
-    demo.source_type = "directory"
-    demo.source_url = path
    check_solver_result(
        ops,
@@ -1405,13 +1530,13 @@ def test_solver_can_resolve_directory_dependencies_with_extras(solver, repo, pac
        / "demo"
    ).as_posix()
-    package.add_dependency("demo", {"path": path, "extras": ["foo"]})
+    package.add_dependency(
+        Factory.create_dependency("demo", {"path": path, "extras": ["foo"]})
+    )
    ops = solver.solve()
-    demo = get_package("demo", "0.1.2")
+    demo = Package("demo", "0.1.2", source_type="directory", source_url=path)
-    demo.source_type = "directory"
-    demo.source_url = path
    check_solver_result(
        ops,
@@ -1441,13 +1566,11 @@ def test_solver_can_resolve_sdist_dependencies(solver, repo, package):
        / "demo-0.1.0.tar.gz"
    ).as_posix()
-    package.add_dependency("demo", {"path": path})
+    package.add_dependency(Factory.create_dependency("demo", {"path": path}))
    ops = solver.solve()
-    demo = get_package("demo", "0.1.0")
+    demo = Package("demo", "0.1.0", source_type="file", source_url=path)
-    demo.source_type = "file"
-    demo.source_url = path
    check_solver_result(
        ops,
@@ -1475,13 +1598,13 @@ def test_solver_can_resolve_sdist_dependencies_with_extras(solver, repo, package
        / "demo-0.1.0.tar.gz"
    ).as_posix()
-    package.add_dependency("demo", {"path": path, "extras": ["foo"]})
+    package.add_dependency(
+        Factory.create_dependency("demo", {"path": path, "extras": ["foo"]})
+    )
    ops = solver.solve()
-    demo = get_package("demo", "0.1.0")
+    demo = Package("demo", "0.1.0", source_type="file", source_url=path)
-    demo.source_type = "file"
-    demo.source_url = path
    check_solver_result(
        ops,
@@ -1511,13 +1634,11 @@ def test_solver_can_resolve_wheel_dependencies(solver, repo, package):
        / "demo-0.1.0-py2.py3-none-any.whl"
    ).as_posix()
-    package.add_dependency("demo", {"path": path})
+    package.add_dependency(Factory.create_dependency("demo", {"path": path}))
    ops = solver.solve()
-    demo = get_package("demo", "0.1.0")
+    demo = Package("demo", "0.1.0", source_type="file", source_url=path)
-    demo.source_type = "file"
-    demo.source_url = path
    check_solver_result(
        ops,
@@ -1545,13 +1666,13 @@ def test_solver_can_resolve_wheel_dependencies_with_extras(solver, repo, package
        / "demo-0.1.0-py2.py3-none-any.whl"
    ).as_posix()
-    package.add_dependency("demo", {"path": path, "extras": ["foo"]})
+    package.add_dependency(
+        Factory.create_dependency("demo", {"path": path, "extras": ["foo"]})
+    )
    ops = solver.solve()
-    demo = get_package("demo", "0.1.0")
+    demo = Package("demo", "0.1.0", source_type="file", source_url=path)
-    demo.source_type = "file"
-    demo.source_url = path
    check_solver_result(
        ops,
@@ -1578,15 +1699,33 @@ def test_solver_can_solve_with_legacy_repository_using_proper_dists(
    solver = Solver(package, pool, installed, locked, io)
-    package.add_dependency("isort", "4.3.4")
+    package.add_dependency(Factory.create_dependency("isort", "4.3.4"))
    ops = solver.solve()
    check_solver_result(
        ops,
        [
-            {"job": "install", "package": get_package("futures", "3.2.0")},
+            {
-            {"job": "install", "package": get_package("isort", "4.3.4")},
+                "job": "install",
+                "package": Package(
+                    "futures",
+                    "3.2.0",
+                    source_type="legacy",
+                    source_url=repo.url,
+                    source_reference=repo.name,
+                ),
+            },
+            {
+                "job": "install",
+                "package": Package(
+                    "isort",
+                    "4.3.4",
+                    source_type="legacy",
+                    source_url=repo.url,
+                    source_reference=repo.name,
+                ),
+            },
        ],
    )
@@ -1604,12 +1743,24 @@ def test_solver_can_solve_with_legacy_repository_using_proper_python_compatible_
    solver = Solver(package, pool, installed, locked, io)
-    package.add_dependency("isort", "4.3.4")
+    package.add_dependency(Factory.create_dependency("isort", "4.3.4"))
    ops = solver.solve()
    check_solver_result(
-        ops, [{"job": "install", "package": get_package("isort", "4.3.4")}]
+        ops,
+        [
+            {
+                "job": "install",
+                "package": Package(
+                    "isort",
+                    "4.3.4",
+                    source_type="legacy",
+                    source_url=repo.url,
+                    source_reference=repo.name,
+                ),
+            }
+        ],
    )
@@ -1621,7 +1772,7 @@ def test_solver_skips_invalid_versions(package, installed, locked, io):
    solver = Solver(package, pool, installed, locked, io)
-    package.add_dependency("trackpy", "^0.4")
+    package.add_dependency(Factory.create_dependency("trackpy", "^0.4"))
    ops = solver.solve()
@@ -1631,8 +1782,12 @@ def test_solver_skips_invalid_versions(package, installed, locked, io):
 def test_multiple_constraints_on_root(package, solver, repo):
-    package.add_dependency("foo", {"version": "^1.0", "python": "^2.7"})
+    package.add_dependency(
-    package.add_dependency("foo", {"version": "^2.0", "python": "^3.7"})
+        Factory.create_dependency("foo", {"version": "^1.0", "python": "^2.7"})
+    )
+    package.add_dependency(
+        Factory.create_dependency("foo", {"version": "^2.0", "python": "^3.7"})
+    )
    foo15 = get_package("foo", "1.5.0")
    foo25 = get_package("foo", "2.5.0")
@@ -1652,7 +1807,7 @@ def test_solver_chooses_most_recent_version_amongst_repositories(
    package, installed, locked, io
 ):
    package.python_versions = "^3.7"
-    package.add_dependency("tomlkit", {"version": "^0.5"})
+    package.add_dependency(Factory.create_dependency("tomlkit", {"version": "^0.5"}))
    repo = MockLegacyRepository()
    pool = Pool([repo, MockPyPIRepository()])
@@ -1665,15 +1820,17 @@ def test_solver_chooses_most_recent_version_amongst_repositories(
        ops, [{"job": "install", "package": get_package("tomlkit", "0.5.3")}]
    )
-    assert "" == ops[0].package.source_type
+    assert ops[0].package.source_type is None
-    assert "" == ops[0].package.source_url
+    assert ops[0].package.source_url is None
 def test_solver_chooses_from_correct_repository_if_forced(
    package, installed, locked, io
 ):
    package.python_versions = "^3.7"
-    package.add_dependency("tomlkit", {"version": "^0.5", "source": "legacy"})
+    package.add_dependency(
+        Factory.create_dependency("tomlkit", {"version": "^0.5", "source": "legacy"})
+    )
    repo = MockLegacyRepository()
    pool = Pool([repo, MockPyPIRepository()])
@@ -1683,7 +1840,19 @@ def test_solver_chooses_from_correct_repository_if_forced(
    ops = solver.solve()
    check_solver_result(
-        ops, [{"job": "install", "package": get_package("tomlkit", "0.5.2")}]
+        ops,
+        [
+            {
+                "job": "install",
+                "package": Package(
+                    "tomlkit",
+                    "0.5.2",
+                    source_type="legacy",
+                    source_url=repo.url,
+                    source_reference=repo.name,
+                ),
+            }
+        ],
    )
    assert "http://legacy.foo.bar" == ops[0].package.source_url
@@ -1693,12 +1862,14 @@ def test_solver_chooses_from_correct_repository_if_forced_and_transitive_depende
    package, installed, locked, io
 ):
    package.python_versions = "^3.7"
-    package.add_dependency("foo", "^1.0")
+    package.add_dependency(Factory.create_dependency("foo", "^1.0"))
-    package.add_dependency("tomlkit", {"version": "^0.5", "source": "legacy"})
+    package.add_dependency(
+        Factory.create_dependency("tomlkit", {"version": "^0.5", "source": "legacy"})
+    )
    repo = Repository()
    foo = get_package("foo", "1.0.0")
-    foo.add_dependency("tomlkit", "^0.5.0")
+    foo.add_dependency(Factory.create_dependency("tomlkit", "^0.5.0"))
    repo.add_package(foo)
    pool = Pool([MockLegacyRepository(), repo, MockPyPIRepository()])
@@ -1709,22 +1880,31 @@ def test_solver_chooses_from_correct_repository_if_forced_and_transitive_depende
    check_solver_result(
        ops,
        [
-            {"job": "install", "package": get_package("tomlkit", "0.5.2")},
+            {
+                "job": "install",
+                "package": Package(
+                    "tomlkit",
+                    "0.5.2",
+                    source_type="legacy",
+                    source_url="http://legacy.foo.bar",
+                    source_reference="legacy",
+                ),
+            },
            {"job": "install", "package": foo},
        ],
    )
    assert "http://legacy.foo.bar" == ops[0].package.source_url
-    assert "" == ops[1].package.source_type
+    assert ops[1].package.source_type is None
-    assert "" == ops[1].package.source_url
+    assert ops[1].package.source_url is None
 def test_solver_does_not_choose_from_secondary_repository_by_default(
    package, installed, locked, io
 ):
    package.python_versions = "^3.7"
-    package.add_dependency("clikit", {"version": "^0.2.0"})
+    package.add_dependency(Factory.create_dependency("clikit", {"version": "^0.2.0"}))
    pool = Pool()
    pool.add_repository(MockPyPIRepository(), secondary=True)
@@ -1737,21 +1917,41 @@ def test_solver_does_not_choose_from_secondary_repository_by_default(
    check_solver_result(
        ops,
        [
-            {"job": "install", "package": get_package("pastel", "0.1.0")},
+            {
+                "job": "install",
+                "package": Package(
+                    "pastel",
+                    "0.1.0",
+                    source_type="legacy",
+                    source_url="http://legacy.foo.bar",
+                    source_reference="legacy",
+                ),
+            },
            {"job": "install", "package": get_package("pylev", "1.3.0")},
-            {"job": "install", "package": get_package("clikit", "0.2.4")},
+            {
+                "job": "install",
+                "package": Package(
+                    "clikit",
+                    "0.2.4",
+                    source_type="legacy",
+                    source_url="http://legacy.foo.bar",
+                    source_reference="legacy",
+                ),
+            },
        ],
    )
    assert "http://legacy.foo.bar" == ops[0].package.source_url
-    assert "" == ops[1].package.source_type
+    assert ops[1].package.source_type is None
-    assert "" == ops[1].package.source_url
+    assert ops[1].package.source_url is None
    assert "http://legacy.foo.bar" == ops[2].package.source_url
 def test_solver_chooses_from_secondary_if_explicit(package, installed, locked, io):
    package.python_versions = "^3.7"
-    package.add_dependency("clikit", {"version": "^0.2.0", "source": "PyPI"})
+    package.add_dependency(
+        Factory.create_dependency("clikit", {"version": "^0.2.0", "source": "PyPI"})
+    )
    pool = Pool()
    pool.add_repository(MockPyPIRepository(), secondary=True)
@@ -1764,17 +1964,26 @@ def test_solver_chooses_from_secondary_if_explicit(package, installed, locked, i
    check_solver_result(
        ops,
        [
-            {"job": "install", "package": get_package("pastel", "0.1.0")},
+            {
+                "job": "install",
+                "package": Package(
+                    "pastel",
+                    "0.1.0",
+                    source_type="legacy",
+                    source_url="http://legacy.foo.bar",
+                    source_reference="legacy",
+                ),
+            },
            {"job": "install", "package": get_package("pylev", "1.3.0")},
            {"job": "install", "package": get_package("clikit", "0.2.4")},
        ],
    )
    assert "http://legacy.foo.bar" == ops[0].package.source_url
-    assert "" == ops[1].package.source_type
+    assert ops[1].package.source_type is None
-    assert "" == ops[1].package.source_url
+    assert ops[1].package.source_url is None
-    assert "" == ops[2].package.source_type
+    assert ops[2].package.source_type is None
-    assert "" == ops[2].package.source_url
+    assert ops[2].package.source_url is None
 def test_solver_discards_packages_with_empty_markers(
@@ -1782,14 +1991,18 @@ def test_solver_discards_packages_with_empty_markers(
 ):
    package.python_versions = "~2.7 || ^3.4"
    package.add_dependency(
-        "a", {"version": "^0.1.0", "markers": "python_version >= '3.4'"}
+        Factory.create_dependency(
+            "a", {"version": "^0.1.0", "markers": "python_version >= '3.4'"}
+        )
    )
    package_a = get_package("a", "0.1.0")
    package_a.add_dependency(
-        "b", {"version": "^0.1.0", "markers": "python_version < '3.2'"}
+        Factory.create_dependency(
+            "b", {"version": "^0.1.0", "markers": "python_version < '3.2'"}
+        )
    )
-    package_a.add_dependency("c", "^0.2.0")
+    package_a.add_dependency(Factory.create_dependency("c", "^0.2.0"))
    package_b = get_package("b", "0.1.0")
    package_c = get_package("c", "0.2.0")
    repo.add_package(package_a)
@@ -1813,8 +2026,16 @@ def test_solver_does_not_raise_conflict_for_conditional_dev_dependencies(
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.5")
-    package.add_dependency("A", {"version": "^1.0", "python": "~2.7"}, category="dev")
+    package.add_dependency(
-    package.add_dependency("A", {"version": "^2.0", "python": "^3.5"}, category="dev")
+        Factory.create_dependency(
+            "A", {"version": "^1.0", "python": "~2.7"}, category="dev"
+        )
+    )
+    package.add_dependency(
+        Factory.create_dependency(
+            "A", {"version": "^2.0", "python": "^3.5"}, category="dev"
+        )
+    )
    package_a100 = get_package("A", "1.0.0")
    package_a200 = get_package("A", "2.0.0")
@@ -1837,12 +2058,18 @@ def test_solver_does_not_loop_indefinitely_on_duplicate_constraints_with_extras(
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.5")
-    package.add_dependency("requests", {"version": "^2.22.0", "extras": ["security"]})
+    package.add_dependency(
+        Factory.create_dependency(
+            "requests", {"version": "^2.22.0", "extras": ["security"]}
+        )
+    )
    requests = get_package("requests", "2.22.0")
-    requests.add_dependency("idna", ">=2.5,<2.9")
+    requests.add_dependency(Factory.create_dependency("idna", ">=2.5,<2.9"))
    requests.add_dependency(
-        "idna", {"version": ">=2.0.0", "markers": "extra == 'security'"}
+        Factory.create_dependency(
+            "idna", {"version": ">=2.0.0", "markers": "extra == 'security'"}
+        )
    )
    requests.extras["security"] = [get_dependency("idna", ">=2.0.0")]
    idna = get_package("idna", "2.8")
@@ -1861,13 +2088,19 @@ def test_solver_does_not_loop_indefinitely_on_duplicate_constraints_with_extras(
 def test_solver_does_not_fail_with_locked_git_and_non_git_dependencies(
    solver, repo, package, locked, pool, installed, io
 ):
-    package.add_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    package.add_dependency(
-    package.add_dependency("a", "^1.2.3")
+        Factory.create_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    )
+    package.add_dependency(Factory.create_dependency("a", "^1.2.3"))
-    git_package = get_package("demo", "0.1.2")
+    git_package = Package(
-    git_package.source_type = "git"
+        "demo",
-    git_package.source_url = "https://github.com/demo/demo.git"
+        "0.1.2",
-    git_package.source_reference = "commit"
+        source_type="git",
+        source_url="https://github.com/demo/demo.git",
+        source_reference="master",
+        source_resolved_reference="commit",
+    )
    installed.add_package(git_package)
@@ -1875,6 +2108,7 @@ def test_solver_does_not_fail_with_locked_git_and_non_git_dependencies(
    locked.add_package(git_package)
    repo.add_package(get_package("a", "1.2.3"))
+    repo.add_package(Package("pendulum", "2.1.2"))
    solver = Solver(package, pool, installed, locked, io)
@@ -1891,9 +2125,15 @@ def test_solver_does_not_fail_with_locked_git_and_non_git_dependencies(
 def test_ignore_python_constraint_no_overlap_dependencies(solver, repo, package):
    pytest = get_package("demo", "1.0.0")
-    pytest.add_dependency("configparser", {"version": "^1.2.3", "python": "<3.2"})
+    pytest.add_dependency(
+        Factory.create_dependency(
+            "configparser", {"version": "^1.2.3", "python": "<3.2"}
+        )
+    )
-    package.add_dependency("demo", {"version": "^1.0.0", "python": "^3.6"})
+    package.add_dependency(
+        Factory.create_dependency("demo", {"version": "^1.0.0", "python": "^3.6"})
+    )
    repo.add_package(pytest)
    repo.add_package(get_package("configparser", "1.2.3"))
@@ -1909,12 +2149,14 @@ def test_solver_should_not_go_into_an_infinite_loop_on_duplicate_dependencies(
    solver, repo, package
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.5")
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
    package_a = get_package("A", "1.0.0")
-    package_a.add_dependency("B")
+    package_a.add_dependency(Factory.create_dependency("B", "*"))
    package_a.add_dependency(
-        "B", {"version": "^1.0", "markers": "implementation_name == 'pypy'"}
+        Factory.create_dependency(
+            "B", {"version": "^1.0", "markers": "implementation_name == 'pypy'"}
+        )
    )
    package_b20 = get_package("B", "2.0.0")
@@ -1964,7 +2206,7 @@ def test_solver_cannot_choose_another_version_for_directory_dependencies(
    pendulum = get_package("pendulum", "2.0.3")
    demo = get_package("demo", "0.1.0")
    foo = get_package("foo", "1.2.3")
-    foo.add_dependency("demo", "<0.1.2")
+    foo.add_dependency(Factory.create_dependency("demo", "<0.1.2"))
    repo.add_package(foo)
    repo.add_package(demo)
    repo.add_package(pendulum)
@@ -1978,8 +2220,8 @@ def test_solver_cannot_choose_another_version_for_directory_dependencies(
        / "demo"
    ).as_posix()
-    package.add_dependency("demo", {"path": path})
+    package.add_dependency(Factory.create_dependency("demo", {"path": path}))
-    package.add_dependency("foo", "^1.2.3")
+    package.add_dependency(Factory.create_dependency("foo", "^1.2.3"))
    # This is not solvable since the demo version is pinned
    # via the directory dependency
@@ -1993,7 +2235,7 @@ def test_solver_cannot_choose_another_version_for_file_dependencies(
    pendulum = get_package("pendulum", "2.0.3")
    demo = get_package("demo", "0.0.8")
    foo = get_package("foo", "1.2.3")
-    foo.add_dependency("demo", "<0.1.0")
+    foo.add_dependency(Factory.create_dependency("demo", "<0.1.0"))
    repo.add_package(foo)
    repo.add_package(demo)
    repo.add_package(pendulum)
@@ -2005,8 +2247,8 @@ def test_solver_cannot_choose_another_version_for_file_dependencies(
        / "demo-0.1.0-py2.py3-none-any.whl"
    ).as_posix()
-    package.add_dependency("demo", {"path": path})
+    package.add_dependency(Factory.create_dependency("demo", {"path": path}))
-    package.add_dependency("foo", "^1.2.3")
+    package.add_dependency(Factory.create_dependency("foo", "^1.2.3"))
    # This is not solvable since the demo version is pinned
    # via the file dependency
@@ -2020,13 +2262,15 @@ def test_solver_cannot_choose_another_version_for_git_dependencies(
    pendulum = get_package("pendulum", "2.0.3")
    demo = get_package("demo", "0.0.8")
    foo = get_package("foo", "1.2.3")
-    foo.add_dependency("demo", "<0.1.0")
+    foo.add_dependency(Factory.create_dependency("demo", "<0.1.0"))
    repo.add_package(foo)
    repo.add_package(demo)
    repo.add_package(pendulum)
-    package.add_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    package.add_dependency(
-    package.add_dependency("foo", "^1.2.3")
+        Factory.create_dependency("demo", {"git": "https://github.com/demo/demo.git"})
+    )
+    package.add_dependency(Factory.create_dependency("foo", "^1.2.3"))
    # This is not solvable since the demo version is pinned
    # via the file dependency
@@ -2053,15 +2297,18 @@ def test_solver_cannot_choose_another_version_for_url_dependencies(
    pendulum = get_package("pendulum", "2.0.3")
    demo = get_package("demo", "0.0.8")
    foo = get_package("foo", "1.2.3")
-    foo.add_dependency("demo", "<0.1.0")
+    foo.add_dependency(Factory.create_dependency("demo", "<0.1.0"))
    repo.add_package(foo)
    repo.add_package(demo)
    repo.add_package(pendulum)
    package.add_dependency(
-        "demo", {"url": "https://foo.bar/distributions/demo-0.1.0-py2.py3-none-any.whl"}
+        Factory.create_dependency(
+            "demo",
+            {"url": "https://foo.bar/distributions/demo-0.1.0-py2.py3-none-any.whl"},
+        )
    )
-    package.add_dependency("foo", "^1.2.3")
+    package.add_dependency(Factory.create_dependency("foo", "^1.2.3"))
    # This is not solvable since the demo version is pinned
    # via the git dependency
@@ -2072,12 +2319,15 @@ def test_solver_cannot_choose_another_version_for_url_dependencies(
 def test_solver_should_not_update_same_version_packages_if_installed_has_no_source_type(
    solver, repo, package, installed
 ):
-    package.add_dependency("foo", "1.0.0")
+    package.add_dependency(Factory.create_dependency("foo", "1.0.0"))
-    foo = get_package("foo", "1.0.0")
+    foo = Package(
-    foo.source_type = "legacy"
+        "foo",
-    foo.source_reference = "custom"
+        "1.0.0",
-    foo.source_url = "https://foo.bar"
+        source_type="legacy",
+        source_url="https://foo.bar",
+        source_reference="custom",
+    )
    repo.add_package(foo)
    installed.add_package(get_package("foo", "1.0.0"))
@@ -2090,10 +2340,14 @@ def test_solver_should_use_the_python_constraint_from_the_environment_if_availab
    solver, repo, package, installed
 ):
    solver.provider.set_package_python_versions("~2.7 || ^3.5")
-    package.add_dependency("A", "^1.0")
+    package.add_dependency(Factory.create_dependency("A", "^1.0"))
    a = get_package("A", "1.0.0")
-    a.add_dependency("B", {"version": "^1.0.0", "markers": 'python_version < "3.2"'})
+    a.add_dependency(
+        Factory.create_dependency(
+            "B", {"version": "^1.0.0", "markers": 'python_version < "3.2"'}
+        )
+    )
    b = get_package("B", "1.0.0")
    b.python_versions = ">=2.6, <3"
@@ -2113,16 +2367,24 @@ def test_solver_should_resolve_all_versions_for_multiple_duplicate_dependencies(
 ):
    package.python_versions = "~2.7 || ^3.5"
    package.add_dependency(
-        "A", {"version": "^1.0", "markers": "python_version < '3.5'"}
+        Factory.create_dependency(
+            "A", {"version": "^1.0", "markers": "python_version < '3.5'"}
+        )
    )
    package.add_dependency(
-        "A", {"version": "^2.0", "markers": "python_version >= '3.5'"}
+        Factory.create_dependency(
+            "A", {"version": "^2.0", "markers": "python_version >= '3.5'"}
+        )
    )
    package.add_dependency(
-        "B", {"version": "^3.0", "markers": "python_version < '3.5'"}
+        Factory.create_dependency(
+            "B", {"version": "^3.0", "markers": "python_version < '3.5'"}
+        )
    )
    package.add_dependency(
-        "B", {"version": "^4.0", "markers": "python_version >= '3.5'"}
+        Factory.create_dependency(
+            "B", {"version": "^4.0", "markers": "python_version >= '3.5'"}
+        )
    )
    package_a10 = get_package("A", "1.0.0")
@@ -2153,7 +2415,9 @@ def test_solver_should_not_raise_errors_for_irrelevant_python_constraints(
 ):
    package.python_versions = "^3.6"
    solver.provider.set_package_python_versions("^3.6")
-    package.add_dependency("dataclasses", {"version": "^0.7", "python": "<3.7"})
+    package.add_dependency(
+        Factory.create_dependency("dataclasses", {"version": "^0.7", "python": "<3.7"})
+    )
    dataclasses = get_package("dataclasses", "0.7")
    dataclasses.python_versions = ">=3.6, <3.7"
@@ -2162,3 +2426,40 @@ def test_solver_should_not_raise_errors_for_irrelevant_python_constraints(
    ops = solver.solve()
    check_solver_result(ops, [{"job": "install", "package": dataclasses}])
+def test_solver_can_resolve_transitive_extras(solver, repo, package):
+    package.add_dependency(Factory.create_dependency("requests", "^2.24.0"))
+    package.add_dependency(Factory.create_dependency("PyOTA", "^2.1.0"))
+    requests = get_package("requests", "2.24.0")
+    requests.add_dependency(Factory.create_dependency("certifi", ">=2017.4.17"))
+    dep = get_dependency("PyOpenSSL", ">=0.14")
+    dep.in_extras.append("security")
+    requests.add_dependency(
+        Factory.create_dependency("PyOpenSSL", {"version": ">=0.14", "optional": True})
+    )
+    requests.extras["security"] = [dep]
+    pyota = get_package("PyOTA", "2.1.0")
+    pyota.add_dependency(
+        Factory.create_dependency(
+            "requests", {"version": ">=2.24.0", "extras": ["security"]}
+        )
+    )
+    repo.add_package(requests)
+    repo.add_package(pyota)
+    repo.add_package(get_package("certifi", "2017.4.17"))
+    repo.add_package(get_package("pyopenssl", "0.14"))
+    ops = solver.solve()
+    check_solver_result(
+        ops,
+        [
+            {"job": "install", "package": get_package("certifi", "2017.4.17")},
+            {"job": "install", "package": get_package("pyopenssl", "0.14")},
+            {"job": "install", "package": requests},
+            {"job": "install", "package": pyota},
+        ],
+    )
--- a/tests/repositories/test_installed_repository.py
+++ b/tests/repositories/test_installed_repository.py
@@ -156,5 +156,5 @@ def test_load_editable_with_import_package(repository):
    assert editable is not None
    assert editable.name == "editable-with-import"
    assert editable.version.text == "2.3.4"
-    assert editable.source_type == ""
+    assert editable.source_type is None
-    assert editable.source_url == ""
+    assert editable.source_url is None
--- a/tests/repositories/test_legacy_repository.py
+++ b/tests/repositories/test_legacy_repository.py
@@ -3,6 +3,7 @@ import shutil
 import pytest
 from poetry.core.packages import Dependency
+from poetry.factory import Factory
 from poetry.repositories.auth import Auth
 from poetry.repositories.exceptions import PackageNotFound
 from poetry.repositories.exceptions import RepositoryError
@@ -117,7 +118,10 @@ def test_get_package_information_skips_dependencies_with_invalid_constraints():
        package.description == "Python Language Server for the Language Server Protocol"
    )
-    assert sorted(package.requires, key=lambda r: r.name) == [
+    assert 19 == len(package.requires)
+    assert sorted(
+        [r for r in package.requires if not r.is_optional()], key=lambda r: r.name
+    ) == [
        Dependency("configparser", "*"),
        Dependency("future", ">=0.14.0"),
        Dependency("futures", "*"),
@@ -142,7 +146,7 @@ def test_get_package_information_skips_dependencies_with_invalid_constraints():
 def test_find_packages_no_prereleases():
    repo = MockRepository()
-    packages = repo.find_packages("pyyaml")
+    packages = repo.find_packages(Factory.create_dependency("pyyaml", "*"))
    assert len(packages) == 1
@@ -154,7 +158,7 @@ def test_find_packages_no_prereleases():
 @pytest.mark.parametrize("constraint,count", [("*", 1), (">=1", 0), (">=19.0.0a0", 1)])
 def test_find_packages_only_prereleases(constraint, count):
    repo = MockRepository()
-    packages = repo.find_packages("black", constraint=constraint)
+    packages = repo.find_packages(Factory.create_dependency("black", constraint))
    assert len(packages) == count
@@ -167,7 +171,7 @@ def test_find_packages_only_prereleases(constraint, count):
 def test_find_packages_only_prereleases_empty_when_not_any():
    repo = MockRepository()
-    packages = repo.find_packages("black", constraint=">=1")
+    packages = repo.find_packages(Factory.create_dependency("black", ">=1"))
    assert len(packages) == 0
@@ -213,6 +217,7 @@ def test_get_package_from_both_py2_and_py3_specific_wheels():
    assert "ipython" == package.name
    assert "5.7.0" == package.version.text
    assert "*" == package.python_versions
+    assert 26 == len(package.requires)
    expected = [
        Dependency("appnope", "*"),
@@ -229,16 +234,17 @@ def test_get_package_from_both_py2_and_py3_specific_wheels():
        Dependency("traitlets", ">=4.2"),
        Dependency("win-unicode-console", ">=0.5"),
    ]
-    assert expected == package.requires
+    required = [r for r in package.requires if not r.is_optional()]
+    assert expected == required
-    assert 'python_version == "2.7"' == str(package.requires[1].marker)
+    assert 'python_version == "2.7"' == str(required[1].marker)
    assert 'sys_platform == "win32" and python_version < "3.6"' == str(
-        package.requires[12].marker
+        required[12].marker
    )
    assert 'python_version == "2.7" or python_version == "3.3"' == str(
-        package.requires[4].marker
+        required[4].marker
    )
-    assert 'sys_platform != "win32"' == str(package.requires[5].marker)
+    assert 'sys_platform != "win32"' == str(required[5].marker)
 def test_get_package_with_dist_and_universal_py3_wheel():
@@ -265,7 +271,8 @@ def test_get_package_with_dist_and_universal_py3_wheel():
        Dependency("typing", "*"),
        Dependency("win-unicode-console", ">=0.5"),
    ]
-    assert expected == sorted(package.requires, key=lambda dep: dep.name)
+    required = [r for r in package.requires if not r.is_optional()]
+    assert expected == sorted(required, key=lambda dep: dep.name)
 def test_get_package_retrieves_non_sha256_hashes():

--- a/tests/repositories/test_pypi_repository.py
+++ b/tests/repositories/test_pypi_repository.py
@@ -9,6 +9,7 @@ from requests.exceptions import TooManyRedirects
 from requests.models import Response
 from poetry.core.packages import Dependency
+from poetry.factory import Factory
 from poetry.repositories.pypi_repository import PyPiRepository
 from poetry.utils._compat import PY35
 from poetry.utils._compat import Path
@@ -56,21 +57,21 @@ class MockRepository(PyPiRepository):
 def test_find_packages():
    repo = MockRepository()
-    packages = repo.find_packages("requests", "^2.18")
+    packages = repo.find_packages(Factory.create_dependency("requests", "^2.18"))
    assert len(packages) == 5
 def test_find_packages_with_prereleases():
    repo = MockRepository()
-    packages = repo.find_packages("toga", ">=0.3.0.dev2")
+    packages = repo.find_packages(Factory.create_dependency("toga", ">=0.3.0.dev2"))
    assert len(packages) == 7
 def test_find_packages_does_not_select_prereleases_if_not_allowed():
    repo = MockRepository()
-    packages = repo.find_packages("pyyaml")
+    packages = repo.find_packages(Factory.create_dependency("pyyaml", "*"))
    assert len(packages) == 1
@@ -78,7 +79,7 @@ def test_find_packages_does_not_select_prereleases_if_not_allowed():
 @pytest.mark.parametrize("constraint,count", [("*", 1), (">=1", 0), (">=19.0.0a0", 1)])
 def test_find_packages_only_prereleases(constraint, count):
    repo = MockRepository()
-    packages = repo.find_packages("black", constraint=constraint)
+    packages = repo.find_packages(Factory.create_dependency("black", constraint))
    assert len(packages) == count
@@ -89,7 +90,8 @@ def test_package():
    package = repo.package("requests", "2.18.4")
    assert package.name == "requests"
-    assert len(package.requires) == 4
+    assert len(package.requires) == 9
+    assert len([r for r in package.requires if r.is_optional()]) == 5
    assert len(package.extras["security"]) == 3
    assert len(package.extras["socks"]) == 2
@@ -141,7 +143,8 @@ def test_fallback_can_read_setup_to_get_dependencies():
    package = repo.package("sqlalchemy", "1.2.12")
    assert package.name == "sqlalchemy"
-    assert len(package.requires) == 0
+    assert len(package.requires) == 9
+    assert len([r for r in package.requires if r.is_optional()]) == 9
    assert package.extras == {
        "mssql_pymssql": [Dependency("pymssql", "*")],
@@ -162,7 +165,10 @@ def test_pypi_repository_supports_reading_bz2_files():
    package = repo.package("twisted", "18.9.0")
    assert package.name == "twisted"
-    assert sorted(package.requires, key=lambda r: r.name) == [
+    assert 28 == len(package.requires)
+    assert sorted(
+        [r for r in package.requires if not r.is_optional()], key=lambda r: r.name
+    ) == [
        Dependency("attrs", ">=17.4.0"),
        Dependency("Automat", ">=0.3.0"),
        Dependency("constantly", ">=15.1"),
@@ -198,7 +204,7 @@ def test_invalid_versions_ignored():
    # the json metadata for this package contains one malformed version
    # and a correct one.
-    packages = repo.find_packages("pygame-music-grid")
+    packages = repo.find_packages(Factory.create_dependency("pygame-music-grid", "*"))
    assert len(packages) == 1
@@ -228,6 +234,6 @@ def test_urls():
 def test_use_pypi_pretty_name():
    repo = MockRepository(fallback=True)
-    package = repo.find_packages("twisted")
+    package = repo.find_packages(Factory.create_dependency("twisted", "*"))
    assert len(package) == 1
    assert package[0].pretty_name == "Twisted"
--- a/tests/test_factory.py
+++ b/tests/test_factory.py
@@ -55,7 +55,7 @@ def test_create_poetry():
    assert not requests.is_vcs()
    assert not requests.allows_prereleases()
    assert requests.is_optional()
-    assert requests.extras == ["security"]
+    assert requests.extras == frozenset(["security"])
    pathlib2 = dependencies["pathlib2"]
    assert pathlib2.pretty_constraint == "^2.2"

--- a/tests/utils/test_env.py
+++ b/tests/utils/test_env.py
@@ -559,7 +559,6 @@ def test_remove_keeps_dir_if_not_deleteable(tmp_dir, manager, poetry, config, mo
    original_rmtree = shutil.rmtree
    def err_on_rm_venv_only(path, *args, **kwargs):
-        print(path)
        if path == str(venv_path):
            raise OSError(16, "Test error")  # ERRNO 16: Device or resource busy
        else:

--- a/tests/utils/test_exporter.py
+++ b/tests/utils/test_exporter.py
@@ -8,10 +8,12 @@ from poetry.repositories.auth import Auth
 from poetry.repositories.legacy_repository import LegacyRepository
 from poetry.utils._compat import Path
 from poetry.utils.exporter import Exporter
+from poetry.utils.toml_file import TomlFile
 class Locker(BaseLocker):
    def __init__(self):
+        self._lock = TomlFile(Path.cwd().joinpath("poetry.lock"))
        self._locked = True
        self._content_hash = self._get_content_hash()

--- a/tests/utils/test_extras.py
+++ b/tests/utils/test_extras.py
 import pytest
 from poetry.core.packages import Package
+from poetry.factory import Factory
 from poetry.utils.extras import get_extra_package_names
 _PACKAGE_FOO = Package("foo", "0.1.0")
 _PACKAGE_SPAM = Package("spam", "0.2.0")
 _PACKAGE_BAR = Package("bar", "0.3.0")
-_PACKAGE_BAR.add_dependency("foo")
+_PACKAGE_BAR.add_dependency(Factory.create_dependency("foo", "*"))
 # recursive dependency
 _PACKAGE_BAZ = Package("baz", "0.4.0")
-_PACKAGE_BAZ.add_dependency("quix")
+_PACKAGE_BAZ.add_dependency(Factory.create_dependency("quix", "*"))
 _PACKAGE_QUIX = Package("quix", "0.5.0")
-_PACKAGE_QUIX.add_dependency("baz")
+_PACKAGE_QUIX.add_dependency(Factory.create_dependency("baz", "*"))
 @pytest.mark.parametrize(