unittest: fix _classmethod_is_defined_at_leaf: use __dict__

Fixes #624.

Author: adamchainz

pytest_django/plugin.py

@@ -268,8 +268,8 @@ def _classmethod_is_defined_at_leaf(cls, method_name):
     super_method = None
 
     for base_cls in cls.__mro__[1:]:  # pragma: no branch
-        if hasattr(base_cls, method_name):
-            super_method = getattr(base_cls, method_name)
+        super_method = base_cls.__dict__.get(method_name)
+        if super_method is not None:
             break
 
     assert super_method is not None, (
@@ -297,7 +297,7 @@ def _disable_class_methods(cls):
 
     _disabled_classmethods[cls] = (
         # Get the classmethod object (not the resulting bound method),
-        # otherwise inheritence will be broken when restoring.
+        # otherwise inheritance will be broken when restoring.
         cls.__dict__.get('setUpClass'),
         _classmethod_is_defined_at_leaf(cls, 'setUpClass'),
         cls.__dict__.get('tearDownClass'),

tests/test_unittest.py

@@ -337,6 +337,34 @@ def test_pass(self):
         ])
         assert result.ret == 0
 
+    def test_setUpClass_leaf_but_not_in_dunder_dict(self, django_testdir):
+        django_testdir.create_test_module('''
+            from django.test import testcases
+
+            class CMSTestCase(testcases.TestCase):
+                pass
+
+            class FooBarTestCase(testcases.TestCase):
+
+                @classmethod
+                def setUpClass(cls):
+                    print('FooBarTestCase.setUpClass')
+                    super(FooBarTestCase, cls).setUpClass()
+
+            class TestContact(CMSTestCase, FooBarTestCase):
+
+                def test_noop(self):
+                    print('test_noop')
+        ''')
+
+        result = django_testdir.runpytest_subprocess('-q', '-s')
+        result.stdout.fnmatch_lines([
+            "*FooBarTestCase.setUpClass*",
+            "*test_noop*",
+            "1 passed*",
+        ])
+        assert result.ret == 0
+
 
 class TestCaseWithDbFixture(TestCase):
     pytestmark = pytest.mark.usefixtures('db')