Island: Simplify logic in test_island_mode.py with fixtures

monkey/tests/unit_tests/monkey_island/cc/resources/test_island_mode.py

@@ -12,7 +12,8 @@ from monkey_island.cc.resources.island_mode import IslandMode as IslandModeResou
 
 
 @pytest.fixture
-def flask_client(build_flask_client):
+def flask_client_builder(build_flask_client):
+    def inner(side_effect=None):
         container = StubDIContainer()
 
         in_memory_simulation_repository = InMemorySimulationRepository()
@@ -20,12 +21,26 @@ def flask_client(build_flask_client):
 
         mock_island_event_queue = MagicMock(spec=IIslandEventQueue)
         mock_island_event_queue.publish.side_effect = (
-        lambda topic, mode: in_memory_simulation_repository.set_mode(mode)
+            side_effect
+            if side_effect
+            else lambda topic, mode: in_memory_simulation_repository.set_mode(mode)
         )
         container.register_instance(IIslandEventQueue, mock_island_event_queue)
 
         with build_flask_client(container) as flask_client:
-        yield flask_client
+            return flask_client
+
+    return inner
+
+
+@pytest.fixture
+def flask_client(flask_client_builder):
+    return flask_client_builder()
+
+
+@pytest.fixture
+def flask_client__internal_server_error(flask_client_builder):
+    return flask_client_builder(Exception)
 
 
 @pytest.mark.parametrize(
@@ -50,22 +65,12 @@ def test_island_mode_post__invalid_mode(flask_client):
     assert resp.status_code == HTTPStatus.UNPROCESSABLE_ENTITY
 
 
-def test_island_mode_post__internal_server_error(build_flask_client):
-    container = StubDIContainer()
-    in_memory_simulation_repository = InMemorySimulationRepository()
-    container.register_instance(ISimulationRepository, in_memory_simulation_repository)
-
-    mock_island_event_queue = MagicMock(spec=IIslandEventQueue)
-    mock_island_event_queue.publish.side_effect = Exception
-    container.register_instance(IIslandEventQueue, mock_island_event_queue)
-
-    with build_flask_client(container) as flask_client:
-        resp = flask_client.put(
+def test_island_mode_post__internal_server_error(flask_client__internal_server_error):
+    resp = flask_client__internal_server_error.put(
         IslandModeResource.urls[0],
         json=IslandMode.RANSOMWARE.value,
         follow_redirects=True,
     )
-
     assert resp.status_code == HTTPStatus.INTERNAL_SERVER_ERROR