effects.test.js中的take测试中，'addDelay/@@end'这个action pattern是干嘛的？现在的npm test会出错

[jibuji]

Code to reproduce the issue: (请提供可复现的代码或者步骤)

it('take', done => {
    const app = create();
    app.model({
      namespace: 'count',
      state: 0,
      reducers: {
        add(state, { payload }) {
          return state + payload || 1;
        },
      },
      effects: {
        *addDelay({ payload }, { put, call }) {
          yield call(delay, payload.delay || 100);
          yield put({ type: 'add', payload: payload.amount });
        },
        *test(action, { put, select, take }) {
          yield put({ type: 'addDelay', payload: { amount: 2 } });
          ** yield take('addDelay/@@end'); **
          const count = yield select(state => state.count);
          yield put({ type: 'addDelay', payload: { amount: count, delay: 0 } });
        },
      },
    });
    app.start();
    app._store.dispatch({ type: 'count/test' });
    setTimeout(() => {
      expect(app._store.getState().count).toEqual(4);
      done();
    }, 300);
  });

上面是一段来自dva/packages/dva-core/test/effects.test.js的代码，里面的yield take('addDelay/@@end');是干嘛的？'addDelay/@@EnD'这种action pattern有什么特殊的含义吗？
我没看懂，请赐教。

Expected behavior: (预期的正常效果)

npm test应该通过

Actual behavior: (实际效果)

npm test 提示错误Cannot find module 'redux' from 'index.js'

Versions of packages used: (哪个库的哪个版本出现的问题)

on master branch commit id: b01c9a6

[ishenli]

@jibuji 看下dva2.0的发布日志：sorrycc/blog#48

[jibuji]

@ishenli, I see, Thank you!