diff --git a/tests/components/mfi/test_sensor.py b/tests/components/mfi/test_sensor.py
index 49efdd5dc71..37512ca78f8 100644
--- a/tests/components/mfi/test_sensor.py
+++ b/tests/components/mfi/test_sensor.py
@@ -116,13 +116,13 @@ async def test_setup_adds_proper_devices(hass: HomeAssistant) -> None:
 
 
 @pytest.fixture(name="port")
-def port_fixture():
+def port_fixture() -> mock.MagicMock:
     """Port fixture."""
     return mock.MagicMock()
 
 
 @pytest.fixture(name="sensor")
-def sensor_fixture(hass, port):
+def sensor_fixture(hass: HomeAssistant, port: mock.MagicMock) -> mfi.MfiSensor:
     """Sensor fixture."""
     sensor = mfi.MfiSensor(port, hass)
     sensor.hass = hass