diff --git a/tests/components/mfi/test_sensor.py b/tests/components/mfi/test_sensor.py
index 39e67d87958..966dcbfd567 100644
--- a/tests/components/mfi/test_sensor.py
+++ b/tests/components/mfi/test_sensor.py
@@ -94,7 +94,7 @@ async def test_setup_adds_proper_devices(hass):
     with mock.patch(
         "homeassistant.components.mfi.sensor.MFiClient"
     ) as mock_client, mock.patch(
-        "homeassistant.components.mfi.sensor.MfiSensor"
+        "homeassistant.components.mfi.sensor.MfiSensor", side_effect=mfi.MfiSensor
     ) as mock_sensor:
         ports = {
             i: mock.MagicMock(model=model) for i, model in enumerate(mfi.SENSOR_MODELS)