diff --git a/tests/unit_tests/extensions/test_cache_middleware.py b/tests/unit_tests/extensions/test_cache_middleware.py
index c69783e3342..e9398032d68 100644
--- a/tests/unit_tests/extensions/test_cache_middleware.py
+++ b/tests/unit_tests/extensions/test_cache_middleware.py
@@ -65,16 +65,16 @@ def test_asset_path_is_intercepted() -> None:
 
 
 def test_nested_asset_path_is_intercepted() -> None:
-    headers = call_middleware(
+    headers: ResponseHeaders = call_middleware(
         "/api/v1/extensions/acme/my-ext/workers/nested/chunk.wasm",
         [("Vary", "Accept-Encoding, Cookie")],
     )
-    vary = dict(headers).get("Vary", "")
+    vary: str = dict(headers).get("Vary", "")
     assert "Cookie" not in vary
 
 
 def test_get_endpoint_with_trailing_slash_is_not_intercepted() -> None:
-    upstream = [("Vary", "Accept-Encoding, Cookie")]
+    upstream: ResponseHeaders = [("Vary", "Accept-Encoding, Cookie")]
     headers = call_middleware("/api/v1/extensions/acme/my-ext/", upstream)
     assert headers == upstream
 
diff --git a/tests/unit_tests/extensions/test_local_extensions_watcher.py b/tests/unit_tests/extensions/test_local_extensions_watcher.py
index 04c7cec3c26..85f2a2bdaac 100644
--- a/tests/unit_tests/extensions/test_local_extensions_watcher.py
+++ b/tests/unit_tests/extensions/test_local_extensions_watcher.py
@@ -21,11 +21,15 @@ from watchdog.events import FileDeletedEvent, FileMovedEvent
 from superset.extensions.local_extensions_watcher import _get_file_handler_class
 
 
+def _noop_schedule_reload(_path: str) -> None:
+    """Stand in for a real debounce timer in unit tests."""
+
+
 def make_handler() -> Any:
     handler_class = _get_file_handler_class()
     handler = handler_class()
     # Avoid spinning up real debounce timers in unit tests.
-    handler._schedule_reload = lambda _path: None
+    handler._schedule_reload = _noop_schedule_reload
     return handler