chore: fix coverage

Author: parthea

noxfile.py

@@ -111,7 +111,7 @@ def default(session, install_grpc=True):
                 "--cov=tests.unit",
                 "--cov-append",
                 "--cov-config=.coveragerc",
-                "--cov-report=",
+                "--cov-report=html",
                 "--cov-fail-under=0",
                 # Running individual tests with parallelism enabled is usually not helpful.
                 "-n=auto",

tests/unit/test_bidi.py

@@ -813,7 +813,7 @@ def test_rpc_callback_fires_when_consumer_start_fails(self):
         bidi_rpc.add_done_callback(callback)
         bidi_rpc._start_rpc.side_effect = expected_exception
 
-        consumer = bidi.BackgroundConsumer(bidi_rpc, on_response=lambda: None)
+        consumer = bidi.BackgroundConsumer(bidi_rpc, on_response=None)
         consumer.start()
         assert callback.call_args.args[0] == expected_exception