redux-mock-store with redux-saga for testing actions / sagas

example.js

// https://github.com/arnaudbenard/redux-mock-store/issues/59#issuecomment-345741265

//------------- the saga ----------------
function* fetchSaga(action) {
   try {
      yield put({type: "FETCH_SUCCEEDED", data: "data"});
   } catch (e) {
      yield put({type: "FETCH_FAILED", message: e.message});
   }
}

function* watchers() {
  yield takeEvery("FETCH", fetchSaga);
}

// -------------- the test -----------------
const sagaMiddleware = createSagaMiddleware();
const mockStore = configureStore([sagaMiddleware]);

describe('the sagas', () => {
  it('should execute YOUR_SAGA', (done) => {
    const store = mockStore({});
    sagaMiddleware.run(watchers); // has to be executed after the mockStore() call

    const expectedActions = [
       { "type": "FETCH" },
       { "type": "FETCH_SUCCEEDED", data: "data"}
    ];

    store.subscribe(() => {
      const actions = store.getActions();
      if (actions.length >= expectedActions.length){
        expect(actions).toEqual(expectedActions);
        done();
      }
    });

    // Return the promise
    store.dispatch({ type: "FETCH" });
  });
});