diff --git a/test/test_log.py b/test/test_log.py
index 0d279f9fb..da808fee1 100644
--- a/test/test_log.py
+++ b/test/test_log.py
@@ -24,7 +24,7 @@
 from ops.model import MAX_LOG_LINE_LEN, _ModelBackend
 
 
-class FakeModelBackend:
+class FakeModelBackend((_ModelBackend)):
 
     def __init__(self):
         self._calls : typing.List[typing.Tuple[str, str]] = []
@@ -49,7 +49,7 @@ def tearDown(self):
         logging.getLogger().handlers.clear()
 
     def test_default_logging(self):
-        ops.log.setup_root_logging(self.backend)  # type: ignore
+        ops.log.setup_root_logging(self.backend)
 
         logger = logging.getLogger()
         self.assertEqual(logger.level, logging.DEBUG)
@@ -72,7 +72,7 @@ def test_default_logging(self):
     def test_handler_filtering(self):
         logger = logging.getLogger()
         logger.setLevel(logging.INFO)
-        logger.addHandler(ops.log.JujuLogHandler(self.backend, logging.WARNING))  # type: ignore
+        logger.addHandler(ops.log.JujuLogHandler(self.backend, logging.WARNING))
         logger.info('foo')
         self.assertEqual(self.backend.calls(), [])
         logger.warning('bar')
@@ -81,7 +81,7 @@ def test_handler_filtering(self):
     def test_no_stderr_without_debug(self):
         buffer = io.StringIO()
         with patch('sys.stderr', buffer):
-            ops.log.setup_root_logging(self.backend, debug=False)  # type: ignore
+            ops.log.setup_root_logging(self.backend, debug=False)
             logger = logging.getLogger()
             logger.debug('debug message')
             logger.info('info message')
@@ -99,7 +99,7 @@ def test_no_stderr_without_debug(self):
     def test_debug_logging(self):
         buffer = io.StringIO()
         with patch('sys.stderr', buffer):
-            ops.log.setup_root_logging(self.backend, debug=True)  # type: ignore
+            ops.log.setup_root_logging(self.backend, debug=True)
             logger = logging.getLogger()
             logger.debug('debug message')
             logger.info('info message')
@@ -121,7 +121,7 @@ def test_debug_logging(self):
         )
 
     def test_reduced_logging(self):
-        ops.log.setup_root_logging(self.backend)  # type: ignore
+        ops.log.setup_root_logging(self.backend)
         logger = logging.getLogger()
         logger.setLevel(logging.WARNING)
         logger.debug('debug')
@@ -133,7 +133,7 @@ def test_long_string_logging(self):
         buffer = io.StringIO()
 
         with patch('sys.stderr', buffer):
-            ops.log.setup_root_logging(self.backend, debug=True)  # type: ignore
+            ops.log.setup_root_logging(self.backend, debug=True)
             logger = logging.getLogger()
             logger.debug('l' * MAX_LOG_LINE_LEN)