diff --git a/tests/dummy_mixer.py b/tests/dummy_mixer.py
index f030ca2..7cdffcc 100644
--- a/tests/dummy_mixer.py
+++ b/tests/dummy_mixer.py
@@ -10,8 +10,9 @@ def create_proxy(config=None):
 class DummyMixer(pykka.ThreadingActor, mixer.Mixer):
     def __init__(self, config):
         super().__init__()
-        self._volume = 50   # Had to be initialised to avoid none type error in tests
-        self._mute = False  # Ditto
+        # These must be initialised to avoid none type error in tests
+        self._volume = 50
+        self._mute = False
 
     def get_volume(self):
         return self._volume
diff --git a/tests/test_frontend.py b/tests/test_frontend.py
index 08c3442..bd6c466 100644
--- a/tests/test_frontend.py
+++ b/tests/test_frontend.py
@@ -27,11 +27,7 @@ def dummy_mopidy_core():
     mixer = dummy_mixer.create_proxy()
     audio = dummy_audio.create_proxy()
     backend = dummy_backend.create_proxy(audio=audio)
-    return core.Core.start(
-        audio=audio,
-        mixer=mixer,
-        backends=[backend]
-    ).proxy()
+    return core.Core.start(audio=audio, mixer=mixer, backends=[backend]).proxy()
 
 
 def test_get_frontend_classes():
@@ -52,7 +48,9 @@ def test_frontend_handler_dispatch_play_pause():
     sys.modules["RPi"] = mock.Mock()
     sys.modules["RPi.GPIO"] = mock.Mock()
 
-    frontend = frontend_lib.RaspberryGPIOFrontend(dummy_config, dummy_mopidy_core())
+    frontend = frontend_lib.RaspberryGPIOFrontend(
+        dummy_config, dummy_mopidy_core()
+    )
 
     frontend.dispatch_input("play_pause")
 
@@ -61,7 +59,9 @@ def test_frontend_handler_dispatch_next():
     sys.modules["RPi"] = mock.Mock()
     sys.modules["RPi.GPIO"] = mock.Mock()
 
-    frontend = frontend_lib.RaspberryGPIOFrontend(dummy_config, dummy_mopidy_core())
+    frontend = frontend_lib.RaspberryGPIOFrontend(
+        dummy_config, dummy_mopidy_core()
+    )
 
     frontend.dispatch_input("next")
 
@@ -70,7 +70,9 @@ def test_frontend_handler_dispatch_prev():
     sys.modules["RPi"] = mock.Mock()
     sys.modules["RPi.GPIO"] = mock.Mock()
 
-    frontend = frontend_lib.RaspberryGPIOFrontend(dummy_config, dummy_mopidy_core())
+    frontend = frontend_lib.RaspberryGPIOFrontend(
+        dummy_config, dummy_mopidy_core()
+    )
 
     frontend.dispatch_input("prev")
 
@@ -79,7 +81,9 @@ def test_frontend_handler_dispatch_volume_up():
     sys.modules["RPi"] = mock.Mock()
     sys.modules["RPi.GPIO"] = mock.Mock()
 
-    frontend = frontend_lib.RaspberryGPIOFrontend(dummy_config, dummy_mopidy_core())
+    frontend = frontend_lib.RaspberryGPIOFrontend(
+        dummy_config, dummy_mopidy_core()
+    )
 
     frontend.dispatch_input("volume_up")
 
@@ -88,7 +92,9 @@ def test_frontend_handler_dispatch_volume_down():
     sys.modules["RPi"] = mock.Mock()
     sys.modules["RPi.GPIO"] = mock.Mock()
 
-    frontend = frontend_lib.RaspberryGPIOFrontend(dummy_config, dummy_mopidy_core())
+    frontend = frontend_lib.RaspberryGPIOFrontend(
+        dummy_config, dummy_mopidy_core()
+    )
 
     frontend.dispatch_input("volume_down")
 
@@ -97,7 +103,9 @@ def test_frontend_handler_dispatch_invalid_event():
     sys.modules["RPi"] = mock.Mock()
     sys.modules["RPi.GPIO"] = mock.Mock()
 
-    frontend = frontend_lib.RaspberryGPIOFrontend(dummy_config, dummy_mopidy_core())
+    frontend = frontend_lib.RaspberryGPIOFrontend(
+        dummy_config, dummy_mopidy_core()
+    )
 
     with pytest.raises(RuntimeError):
         frontend.dispatch_input("tomato")
@@ -107,6 +115,8 @@ def test_frontend_gpio_event():
     sys.modules["RPi"] = mock.Mock()
     sys.modules["RPi.GPIO"] = mock.Mock()
 
-    frontend = frontend_lib.RaspberryGPIOFrontend(dummy_config, dummy_mopidy_core())
+    frontend = frontend_lib.RaspberryGPIOFrontend(
+        dummy_config, dummy_mopidy_core()
+    )
 
     frontend.gpio_event(3)
diff --git a/tox.ini b/tox.ini
index d92eb3d..d4deebc 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,4 +20,4 @@ commands = python -m check_manifest
 
 [testenv:flake8]
 deps = .[lint]
-commands = python -m flake8 --ignore=B950 --show-source --statistics
+commands = python -m flake8 --ignore=B950,B305,E501 --show-source --statistics