使用redux-mock-store进行单元测试--我怎样才能让这个单元测试通过？

import configureMockStore from 'redux-mock-store';
import thunk from 'redux-thunk';
import { fetchUser, FETCH_USER_SUCCESS } from './actions';
import reducer from './reducer';

const middlewares = [thunk];
const mockStore = configureMockStore(middlewares);

describe('fetchUser', () => {
  it('should dispatch FETCH_USER_SUCCESS action', () => {
    const initialState = {};
    const store = mockStore(initialState);

    // 调用action creator并分发action
    return store.dispatch(fetchUser())
      .then(() => {
        const actions = store.getActions();
        // 断言期望的结果
        expect(actions[0].type).toEqual(FETCH_USER_SUCCESS);
        expect(actions[0].payload).toEqual({ name: 'John' });
      });
  });
});

describe('reducer', () => {
  it('should handle FETCH_USER_SUCCESS action', () => {
    const initialState = {};
    const action = {
      type: FETCH_USER_SUCCESS,
      payload: { name: 'John' }
    };

    // 调用reducer并获取新的状态
    const newState = reducer(initialState, action);

    // 断言期望的结果
    expect(newState.user).toEqual({ name: 'John' });
  });
});