private void setupMockServer(HashMap<String, String> override_map) {
    HashMap<String, String> map = new HashMap<>(Util.RESPONSE_MAP);

    if (override_map != null) {
      for (String key : override_map.keySet()) {
        map.put(key, override_map.get(key));
      }
    }

    Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
    AndroidApplication app =
        (AndroidApplication) instrumentation.getTargetContext().getApplicationContext();

    // setup objectGraph to inject Mock API
    List modules = Collections.singletonList(new DummyAPIModule(map));
    ObjectGraph graph = ObjectGraph.create(modules.toArray());
    app.setObjectGraph(graph);
    app.getObjectGraph().inject(app);
  }