我如何测试 redux .subscribe()

Question

在我想要测试的代码中，有 store.subscribe() 函数，但我不知道如何测试它。

test('should call console.log inside subscribe fn', async () => {
  const store = configureStore(initialState);
  store.subscribe(() => console.log(store.getState())); // console.log was not called

  await wait(100);
})

在我的代码中

// index.ts

export const store = createStore();
store.subscribe(() => console.log(store.getState())); // how can i test it in jest?

Answer 1

你想测试subscriber函数，那么你可以通过dispatch action来触发它。在调度每个动作后断言状态。

import { configureStore } from '@reduxjs/toolkit';

test('should call console.log inside subscribe fn', async () => {
  expect.assertions(1);
  const store = configureStore({ reducer: (state = 'test state') => state });
  store.subscribe(() => {
    expect(store.getState()).toEqual('test state');
  });
  store.dispatch({ type: '' });
});

测试结果：

 PASS   redux-toolkit-example  packages/redux-toolkit-example/stackoverflow/69845750/index.test.ts
  ✓ should call console.log inside subscribe fn (4 ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        3.869 s