Fix docs formatting and improve test a bit

testing/test_collection.py

@@ -639,18 +639,21 @@ def test_global_file(self, testdir, tmpdir):
 
     def test_pkgfile(self, testdir):
         """Verify nesting when a module is within a package.
-	The parent chain should match: Module<x.py> -> Package<subdir> -> Session.
-        Session's parent should always be None.
-	"""
+        The parent chain should match: Module<x.py> -> Package<subdir> -> Session.
+            Session's parent should always be None.
+        """
         tmpdir = testdir.tmpdir
         subdir = tmpdir.join("subdir")
         x = subdir.ensure("x.py")
         subdir.ensure("__init__.py")
         with subdir.as_cwd():
             config = testdir.parseconfigure(x)
         col = testdir.getnode(config, x)
-        assert isinstance(col, pytest.Module)
         assert col.name == "x.py"
+        assert isinstance(col, pytest.Module)
+        assert isinstance(col.parent, pytest.Package)
+        assert isinstance(col.parent.parent, pytest.Session)
+        # session is batman (has no parents)
         assert col.parent.parent.parent is None
         for col in col.listchain():
             assert col.config is config