Add unit tests for not overriding setUpClass

We ensure that if setUpClass is implemented by a test class,
it must invoke the super setUpClass. Adding unit test for it.

Change-Id: I50993b6d76cc462e533b243b7bf28d1b2c2228ff

tempest/test.py

@@ -98,14 +98,15 @@ class BaseTestCase(testtools.testcase.WithAttributes,
     - resource_cleanup
     """
 
-    setUpClassCalled = False
-
     # NOTE(andreaf) credentials holds a list of the credentials to be allocated
     # at class setup time. Credential types can be 'primary', 'alt', 'admin' or
     # a list of roles - the first element of the list being a label, and the
     # rest the actual roles
     credentials = []
 
+    # Track if setUpClass was invoked
+    __setupclass_called = False
+
     # Network resources to be provisioned for the requested test credentials.
     # Only used with the dynamic credentials provider.
     _network_resources = {}
@@ -133,18 +134,19 @@ class BaseTestCase(testtools.testcase.WithAttributes,
         cls.__setup_credentials_called = False
         cls.__resource_cleanup_called = False
         cls.__skip_checks_called = False
+        # Stack of callable to be invoked in reverse order
         cls._class_cleanups = []
+        # Stack of (name, callable) to be invoked in reverse order at teardown
+        cls._teardowns = []
 
     @classmethod
     def setUpClass(cls):
+        cls.__setupclass_called = True
         # Reset state
         cls._reset_class()
         # It should never be overridden by descendants
         if hasattr(super(BaseTestCase, cls), 'setUpClass'):
             super(BaseTestCase, cls).setUpClass()
-        cls.setUpClassCalled = True
-        # Stack of (name, callable) to be invoked in reverse order at teardown
-        cls._teardowns = []
         # All the configuration checks that may generate a skip
         cls.skip_checks()
         if not cls.__skip_checks_called:
@@ -579,7 +581,7 @@ class BaseTestCase(testtools.testcase.WithAttributes,
 
     def setUp(self):
         super(BaseTestCase, self).setUp()
-        if not self.setUpClassCalled:
+        if not self.__setupclass_called:
             raise RuntimeError("setUpClass does not calls the super's"
                                "setUpClass in the "
                                + self.__class__.__name__)

tempest/tests/test_test.py

@@ -453,6 +453,26 @@ class TestTempestBaseTestClass(base.TestCase):
             expected_creds[1][1:],
             mock_get_client_manager.mock_calls[1][2]['roles'])
 
+    def test_setup_class_overwritten(self):
+
+        class OverridesSetup(self.parent_test):
+
+            @classmethod
+            def setUpClass(cls):  # noqa
+                pass
+
+        overrides_setup = OverridesSetup()
+        suite = unittest.TestSuite((overrides_setup,))
+        log = []
+        result = LoggingTestResult(log)
+        suite.run(result)
+        # Record 0, test (error holder). The error generates during test run.
+        self.assertIn('runTest', str(log[0][0]))
+        # Record 0, traceback
+        self.assertRegex(
+            str(log[0][2]['traceback']).replace('\n', ' '),
+            RuntimeError.__name__ + ': .* ' + OverridesSetup.__name__)
+
 
 class TestTempestBaseTestClassFixtures(base.TestCase):