Fix tests on Windows

poetry/utils/_compat.py

 import sys
 
 try:
-    import pathlib2
-    from pathlib2 import Path
-except ImportError:
-    from pathlib import Path
-
-try:
     from functools32 import lru_cache
 except ImportError:
     from functools import lru_cache
@@ -26,6 +20,12 @@ PY35 = sys.version_info >= (3, 5)
 PY36 = sys.version_info >= (3, 6)
 
 
+if PY35:
+    from pathlib import Path
+else:
+    from pathlib2 import Path
+
+
 def decode(string, encodings=None):
     if not PY2 and not isinstance(string, bytes):
         return string

tests/installation/test_installer.py

@@ -91,7 +91,10 @@ def setup():
 
 @pytest.fixture()
 def package():
-    return ProjectPackage("root", "1.0")
+    p = ProjectPackage("root", "1.0")
+    p.root_dir = Path.cwd()
+
+    return p
 
 
 @pytest.fixture()