Fixed #27214 -- Made skip db features decorators respect wrapping order and inheritance.

django/test/testcases.py

@@ -1083,11 +1083,23 @@ class TestCase(TransactionTestCase):
 
 class CheckCondition(object):
     """Descriptor class for deferred condition checking"""
-    def __init__(self, cond_func):
-        self.cond_func = cond_func
+    def __init__(self, *conditions):
+        self.conditions = conditions
+
+    def add_condition(self, condition, reason):
+        return self.__class__(*self.conditions + ((condition, reason),))
 
     def __get__(self, instance, cls=None):
-        return self.cond_func()
+        # Trigger access for all bases.
+        if any(getattr(base, '__unittest_skip__', False) for base in cls.__bases__):
+            return True
+        for condition, reason in self.conditions:
+            if condition():
+                # Override this descriptor's value and set the skip reason.
+                cls.__unittest_skip__ = True
+                cls.__unittest_skip_why__ = reason
+                return True
+        return False
 
 
 def _deferredSkip(condition, reason):
@@ -1103,8 +1115,13 @@ def _deferredSkip(condition, reason):
         else:
             # Assume a class is decorated
             test_item = test_func
-            test_item.__unittest_skip__ = CheckCondition(condition)
-        test_item.__unittest_skip_why__ = reason
+            # Retrieve the possibly existing value from the class's dict to
+            # avoid triggering the descriptor.
+            skip = test_func.__dict__.get('__unittest_skip__')
+            if isinstance(skip, CheckCondition):
+                test_item.__unittest_skip__ = skip.add_condition(condition, reason)
+            elif skip is not True:
+                test_item.__unittest_skip__ = CheckCondition((condition, reason))
         return test_item
     return decorator
 

tests/test_utils/tests.py

@@ -106,20 +106,28 @@ class SkippingClassTestCase(SimpleTestCase):
             def test_dummy(self):
                 return
 
+        @skipUnlessDBFeature("missing")
         @skipIfDBFeature("__class__")
         class SkippedTests(unittest.TestCase):
             def test_will_be_skipped(self):
                 self.fail("We should never arrive here.")
 
+        @skipIfDBFeature("__dict__")
+        class SkippedTestsSubclass(SkippedTests):
+            pass
+
         test_suite = unittest.TestSuite()
         test_suite.addTest(NotSkippedTests('test_dummy'))
         try:
             test_suite.addTest(SkippedTests('test_will_be_skipped'))
+            test_suite.addTest(SkippedTestsSubclass('test_will_be_skipped'))
         except unittest.SkipTest:
             self.fail("SkipTest should not be raised at this stage")
         result = unittest.TextTestRunner(stream=six.StringIO()).run(test_suite)
-        self.assertEqual(result.testsRun, 2)
-        self.assertEqual(len(result.skipped), 1)
+        self.assertEqual(result.testsRun, 3)
+        self.assertEqual(len(result.skipped), 2)
+        self.assertEqual(result.skipped[0][1], 'Database has feature(s) __class__')
+        self.assertEqual(result.skipped[1][1], 'Database has feature(s) __class__')
 
 
 @override_settings(ROOT_URLCONF='test_utils.urls')