Refs #32417 -- Improved cleaning up and fixed isolation of staticfiles_tests tests.

tests/staticfiles_tests/test_liveserver.py

@@ -29,13 +29,22 @@ class LiveServerBase(StaticLiveServerTestCase):
         # Override settings
         cls.settings_override = override_settings(**TEST_SETTINGS)
         cls.settings_override.enable()
-        super().setUpClass()
+        try:
+            super().setUpClass()
+        except Exception:
+            # Clean up since tearDownClass() isn't called on errors.
+            cls._tearDownLiveServerBase()
+            raise
+
+    @classmethod
+    def _tearDownLiveServerBase(cls):
+        # Restore original settings
+        cls.settings_override.disable()
 
     @classmethod
     def tearDownClass(cls):
         super().tearDownClass()
-        # Restore original settings
-        cls.settings_override.disable()
+        cls._tearDownLiveServerBase()
 
 
 class StaticLiveServerChecks(LiveServerBase):
@@ -46,8 +55,10 @@ class StaticLiveServerChecks(LiveServerBase):
         # should bubble up to the main thread.
         old_STATIC_URL = TEST_SETTINGS['STATIC_URL']
         TEST_SETTINGS['STATIC_URL'] = None
-        cls.raises_exception()
-        TEST_SETTINGS['STATIC_URL'] = old_STATIC_URL
+        try:
+            cls.raises_exception()
+        finally:
+            TEST_SETTINGS['STATIC_URL'] = old_STATIC_URL
 
     @classmethod
     def tearDownClass(cls):
@@ -58,16 +69,14 @@ class StaticLiveServerChecks(LiveServerBase):
     def raises_exception(cls):
         try:
             super().setUpClass()
-            raise Exception("The line above should have raised an exception")
         except ImproperlyConfigured:
             # This raises ImproperlyConfigured("You're using the staticfiles
             # app without having set the required STATIC_URL setting.")
             pass
-        finally:
-            # Use del to avoid decrementing the database thread sharing count a
-            # second time.
-            del cls.server_thread
+        else:
+            # super().setUpClass() cleans up after itself on a failure.
             super().tearDownClass()
+            raise Exception('setUpClass() should have raised an exception.')
 
     def test_test_test(self):
         # Intentionally empty method so that the test is picked up by the