使用Redux对象的DeepFreeze测试突变

Question

我有一个简单的Reducer

const uid = () => Math.random().toString(34).slice(2);
const bots = (state = [] , action) => {

    switch(action.type) {    
      case 'ADD_BOT':

          return [
              ...state, {
                    id: uid(),
                    isDone: false,
                    text: action.bots.text
              }
          ]

          //this will fail
     case 'ADD_BOT_THAT_MUTATES':
          console.log("mutating");
          action.bots.id = uid();
          state.push(action.bots);
          return state;

      default:
        return state;
  }
}
export default bots

我的规范文件是

import deepFreeze from 'deep-freeze';
import bots from '../bots';

describe('Simple test', () =>  {

 function addBot(text) {
  return {
    type: 'ADD_BOT',
    bots: {
      id: 1,
      isDone: false,
      text: text
    }
  };
 }

 function addBotThatMutates(text) {
  return {
    type: 'ADD_BOT_THAT_MUTATES',
    bots: {
      id: 1,
      isDone: false,
      text: text
    }
  };
 }

  let state = []; 
  deepFreeze(state); 

  beforeEach(() => {

        state = bots(state, addBot("initial"));

  });

    it('should fail due to deepFreeze', () => {

        //create a payload
        let payload = addBot("test 1234");
        let payloadThatMutates = addBotThatMutates("test 5678");

        state = bots(state, payload);

        state = bots(state, payloadThatMutates);

        expect(3).toEqual(state.length);
    });
});

当我用state = bots(state, payload);调用Reducer时，我希望它会返回一个非变异数组，因为我在Reducer中使用了ES6 spread语句。

当我调用state = bots(state, payloadThatMutates);时，我期待着一个由deepFreeze标记的错误。这是因为在减速器中，我使用的是state.push(action.bots);，我知道它会发生变异。

但是我没有得到任何错误，并且我的结果状态是一个由3个对象组成的数组。

我有一个错误的减速器，或者我不理解deepFreeze？

这个单元测试并没有像我期望的那样工作。但是，如果我调用'ADD_BOT_THAT_MUTATES操作和Reducer，我没有得到更新的状态，即Redux改变了状态，那么我的应用程序/网络代码就可以工作。

还是我刚刚做了什么愚蠢的事？

Answer 1

自从发帖以来，我已经设法理解了deepFreeze，下面是我的两个测试，它们给出了预期的结果

import deepFreeze from 'deep-freeze';
import bots from '../bots';

describe('Simple test', () =>  {

 function addBot(text) {
  return {
    type: 'ADD_BOT',
    bots: {
      id: 1,
      isDone: false,
      text: text
    }
  };
 }

 function addBotThatMutates(text) {
  return {
    type: 'ADD_BOT_THAT_MUTATES',
    bots: {
      id: 1,
      isDone: false,
      text: text
    }
  };
 }

  let state; 

  beforeEach(() => {        
    state = []
        state = bots(state, addBot("initial"));  
  });

    it('should pass due to non-muting reducer ', () => {
        //create a payload
        let payload = addBot("test 1234");
        let state2 = bots(state, payload);
        //state  has non mutated and state2 is a new array
         expect(state.length).toEqual(1);
         expect(state2.length).toEqual(2);
    });

  it('should fail due to deepFreeze', () => {
          deepFreeze(state); 
          //create a payload
          let payloadThatMutates = addBotThatMutates("test 5678");
          //deepFreeze will throw 'object is not extensible' because state is now mutating because of the push in the the reducer
          let state2 = bots(state, payloadThatMutates);          
          expect(state).toEqual(state2);
    });

});

希望这对任何人都有帮助