Use mixin-composition not inheritance for LoggingTestCase

We used inheritence to add additional logging assertion methods to unittest's TestCase class. However, with the introduction of the new IsolatedAsyncioTestCase this extension strategy means we'd have to create multiple child classes to be able to use the extended functionality in all of the TestCase variants.

Since that leads to undesirable code reuse and an inheritance relationship is not at all needed, I've switched to a mixin-composition based approach that allows the user to extend the functionality of any TestCase variant with a mixin where needed.

1 files changed, 6 insertions, 12 deletions

diff --git a/tests/test_base.py b/tests/test_base.py
index a16e2af8f..23abb1dfd 100644
--- a/tests/test_base.py
+++ b/tests/test_base.py
@@ -3,7 +3,11 @@ import unittest
 import unittest.mock
 
 
-from tests.base import LoggingTestCase, _CaptureLogHandler
+from tests.base import LoggingTestsMixin, _CaptureLogHandler
+
+
+class LoggingTestCase(LoggingTestsMixin):
+    pass
 
 
 class LoggingTestCaseTests(unittest.TestCase):
@@ -18,19 +22,9 @@ class LoggingTestCaseTests(unittest.TestCase):
         try:
             with LoggingTestCase.assertNotLogs(self, level=logging.DEBUG):
                 pass
-        except AssertionError:
+        except AssertionError:  # pragma: no cover
             self.fail("`self.assertNotLogs` raised an AssertionError when it should not!")
 
-    @unittest.mock.patch("tests.base.LoggingTestCase.assertNotLogs")
-    def test_the_test_function_assert_not_logs_does_not_raise_with_no_logs(self, assertNotLogs):
-        """Test if test_assert_not_logs_does_not_raise_with_no_logs captures exception correctly."""
-        assertNotLogs.return_value = iter([None])
-        assertNotLogs.side_effect = AssertionError
-
-        message = "`self.assertNotLogs` raised an AssertionError when it should not!"
-        with self.assertRaises(AssertionError, msg=message):
-            self.test_assert_not_logs_does_not_raise_with_no_logs()
-
     def test_assert_not_logs_raises_correct_assertion_error_when_logs_are_emitted(self):
         """Test if LoggingTestCase.assertNotLogs raises AssertionError when logs were emitted."""
         msg_regex = (