Fix tests for Python 2.7

tests/console/commands/test_check.py

 from cleo.testers import CommandTester
 
+from poetry.utils._compat import PY2
 from poetry.utils._compat import Path
 from poetry.poetry import Poetry
 
@@ -26,6 +27,13 @@ def test_check_invalid(app):
 
     tester.execute([("command", command.get_name())])
 
+    if PY2:
+        expected = """\
+Error: u'description' is a required property
+Error: INVALID is not a valid license
+Warning: A wildcard Python dependency is ambiguous. Consider specifying a more explicit one.
+"""
+    else:
         expected = """\
 Error: 'description' is a required property
 Error: INVALID is not a valid license

tests/test_poetry.py

@@ -2,10 +2,8 @@
 from __future__ import absolute_import
 from __future__ import unicode_literals
 
-import pytest
-
-from poetry.exceptions import InvalidProjectFile
 from poetry.poetry import Poetry
+from poetry.utils._compat import PY2
 from poetry.utils._compat import Path
 from poetry.utils.toml_file import TomlFile
 
@@ -145,10 +143,16 @@ def test_check_fails():
     complete = TomlFile(fixtures_dir / "complete.toml")
     content = complete.read()["tool"]["poetry"]
     content["this key is not in the schema"] = ""
-    assert Poetry.check(content) == {
-        "errors": [
+
+    if PY2:
+        expected = (
+            "Additional properties are not allowed "
+            "(u'this key is not in the schema' was unexpected)"
+        )
+    else:
+        expected = (
             "Additional properties are not allowed "
             "('this key is not in the schema' was unexpected)"
-        ],
-        "warnings": [],
-    }
+        )
+
+    assert Poetry.check(content) == {"errors": [expected], "warnings": []}