diff --git a/tests/mock_responses.py b/tests/mock_responses.py
index ca9c18e93ff6fd2fbb021cffd47a64cb6ed1c587..9d2d534e37e6e2220a5ca14c0723300899f452e6 100644
--- a/tests/mock_responses.py
+++ b/tests/mock_responses.py
@@ -37,12 +37,16 @@ class EmptyResponse:
         pass
 
 
-def CoroMock(return_value=...):
+def CoroMock(return_value=None):
     """Corountine mocking object.
 
     For an example, see test_coro_mock.py.
 
     Source: http://stackoverflow.com/a/32505333/875379
+
+    :param return_value: whatever you want to have set as return value.
+        This must always be set. Pass the ellipsis object ... to not set this; in that case
+        you are responsible yourself to set coromock.coro.return_value.
     """
 
     import asyncio
diff --git a/tests/test_may_i_run.py b/tests/test_may_i_run.py
index 7ffeb29b5068c6c5639094831c4f14fce88383d5..ce6e7bc155c42f78b6cf595589da2911c1480795 100644
--- a/tests/test_may_i_run.py
+++ b/tests/test_may_i_run.py
@@ -1,5 +1,3 @@
-import typing
-
 from unittest.mock import Mock
 
 from abstract_worker_test import AbstractWorkerTest
@@ -16,7 +14,6 @@ class MayIRunTest(AbstractWorkerTest):
 
         self.loop = construct_asyncio_loop()
         self.manager = Mock(spec=FlamencoManager)
-        self.manager.get = Mock()
         self.worker = Mock(spec=FlamencoWorker)
         self.shutdown_future = self.loop.create_future()
 
@@ -25,22 +22,23 @@ class MayIRunTest(AbstractWorkerTest):
                            poll_interval=timedelta(seconds=0.2),
                            loop=self.loop)
 
-    def _mock_get(self, *json_responses: dict):
-        import collections
-        values = collections.deque(json_responses)
+    def _mock_get(self, *json_responses):
+        from collections import deque
+
+        values = deque(json_responses)
 
         async def mocked_get(*args, **kwargs):
-            mock_resp = Mock()
-            mock_resp.json.return_value = values.popleft()
-            return mock_resp
+            mocked_response = Mock()
+            mocked_response.json.return_value = values.popleft()
+            return mocked_response
 
         self.manager.get = mocked_get
 
     def test_may_i_run_false(self):
         self._mock_get({
-                'may_keep_running': False,
-                'reason': 'je moeder',
-            })
+            'may_keep_running': False,
+            'reason': 'je moeder',
+        })
 
         result = self.loop.run_until_complete(self.mir.may_i_run('1234'))
         self.assertFalse(result)
diff --git a/tests/test_runner_blender_render.py b/tests/test_runner_blender_render.py
index 4908965e6bb62e8b69de4728557327db3c2ca232..9ceeb6f44883c3ba63464636482e1233722212f5 100644
--- a/tests/test_runner_blender_render.py
+++ b/tests/test_runner_blender_render.py
@@ -81,7 +81,7 @@ class BlenderRenderTest(AbstractCommandTest):
             'filepath': filepath,
         }
 
-        cse = CoroMock()
+        cse = CoroMock(...)
         cse.coro.return_value.wait = CoroMock(return_value=0)
         with patch('asyncio.create_subprocess_exec', new=cse) as mock_cse:
             self.loop.run_until_complete(self.cmd.run(settings))