bring in purepath and fix an assertion

src/_pytest/compat.py

@@ -23,7 +23,7 @@
     # Only available in Python 3.4+ or as a backport
     enum = None
 
-__all__ = ["Path"]
+__all__ = ["Path", "PurePath"]
 
 _PY3 = sys.version_info > (3, 0)
 _PY2 = not _PY3
@@ -42,9 +42,9 @@
 MODULE_NOT_FOUND_ERROR = "ModuleNotFoundError" if PY36 else "ImportError"
 
 if PY36:
-    from pathlib import Path
+    from pathlib import Path, PurePath
 else:
-    from pathlib2 import Path
+    from pathlib2 import Path, PurePath
 
 
 if _PY3:

src/pytest.py

@@ -26,6 +26,7 @@
     RemovedInPytest4Warning,
     PytestExperimentalApiWarning,
 )
+from _pytest.compat import Path, PurePath
 
 set_trace = __pytestPDB.set_trace
 
@@ -67,6 +68,8 @@
     "warns",
     "xfail",
     "yield_fixture",
+    "Path",
+    "PurePath",
 ]
 
 if __name__ == "__main__":

testing/test_tmpdir.py

@@ -111,7 +111,7 @@ def test_tmpdir_factory(testdir):
         def session_dir(tmpdir_factory):
             return tmpdir_factory.mktemp('data', numbered=False)
         def test_some(session_dir):
-            session_dir.isdir()
+            assert session_dir.isdir()
     """
     )
     reprec = testdir.inline_run()