使用 mocha/chai 进行基本的 React/redux 测试

Question

我是 react/redux 世界的新手，我使用 this code 创建了 redux 待办事项应用程序，现在我想为它编写测试，我创建了以下规范：

import {expect} from 'chai'
import todoApp from '../src/reducers'
import {setVisibilityFilter} from '../src/actions'

describe('reducer', ()=> {
    it('Set correctly visibility filter', ()=>{
        const setVisibilityFilterAction = setVisibilityFilter('SHOW_ALL')
        const initialState={};
        const nextState= todoApp(initialState, setVisibilityFilterAction)
        const expectedState ={
                todos:[],
                visibilityFilter:'SHOW_ALL' 
            }
        expect(nextState).to.equal(expectedState);
    })
})  

但是断言失败并且错误是：

AssertionError: expected { Object (todos, visibilityFilter) } to equal { Object (todos, visibilityFilter) }
      + expected - actual

尝试打印对象，它们（expectedState 和 nextState）都具有相同的数据：

{
   todos:[],
   visibilityFilter: "SHOW_ALL"
}

为什么会失败？

Answer 1

来自 Chai 的expect 接口的equal() 是严格的相等检查。听起来你想要eql() 或.deep.equal()。

// Equivalent to nextState === expectedState
expect(nextState).to.equal(expectedState);

// Instead:
expect(nextState).to.eql(expectedState);

// Or:
expect(nextState).to.deep.equal(expectedState);