Fix docs formatting and improve test a bit

testing/test_collection.py

@@ -649,8 +649,11 @@ class Test_getinitialnodes(object):
         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