如何在Jest中设置模拟日期? [英] How do I set a mock date in Jest?

问题描述

我正在使用moment.js在React组件的帮助器文件中执行大多数日期逻辑，但是我还无法弄清楚如何在Jest a la sinon.useFakeTimers()中模拟日期.

I'm using moment.js to do most of my date logic in a helper file for my React components but I haven't been able to figure out how to mock a date in Jest a la sinon.useFakeTimers().

Jest文档仅谈论setTimeout，setInveral等计时器函数，但无助于设置日期，然后检查我的date函数是否完成了它们打算做的事情.

The Jest docs only speak about timer functions like setTimeout, setInveral etc but don't help with setting a date and then checking that my date functions do what they're meant to do.

这是我的一些JS文件:

Here is some of my JS file:

var moment = require('moment');

var DateHelper = {

  DATE_FORMAT: 'MMMM D',
  API_DATE_FORMAT: 'YYYY-MM-DD',

  formatDate: function(date) {
    return date.format(this.DATE_FORMAT);
  },

  isDateToday: function(date) {
    return this.formatDate(date) === this.formatDate(moment());
  }
};

module.exports = DateHelper;

这是我使用Jest设置的内容:

and here is what I've set up using Jest:

jest.dontMock('../../../dashboard/calendar/date-helper')
    .dontMock('moment');

describe('DateHelper', function() {
  var DateHelper = require('../../../dashboard/calendar/date-helper'),
      moment = require('moment'),
      DATE_FORMAT = 'MMMM D';

  describe('formatDate', function() {

    it('should return the date formatted as DATE_FORMAT', function() {
      var unformattedDate = moment('2014-05-12T00:00:00.000Z'),
          formattedDate = DateHelper.formatDate(unformattedDate);

      expect(formattedDate).toEqual('May 12');
    });

  });

  describe('isDateToday', function() {

    it('should return true if the passed in date is today', function() {
      var today = moment();

      expect(DateHelper.isDateToday(today)).toEqual(true);
    });

  });

});

现在这些测试通过了，因为我使用的是我的时刻，而我的函数使用的是时刻，但是似乎有点不稳定，我想将日期设置为固定的时间进行测试.

Now these tests pass because I'm using moment and my functions use moment but it seems a bit unstable and I would like to set the date to a fixed time for the tests.

关于如何实现的任何想法?

Any idea on how that could be accomplished?

推荐答案

MockDate 可用于开玩笑的测试中进行更改new Date()返回什么:

MockDate can be used in jest tests to change what new Date() returns:

var MockDate = require('mockdate');
// I use a timestamp to make sure the date stays fixed to the ms
MockDate.set(1434319925275);
// test code here
// reset to native Date()
MockDate.reset();

这篇关于如何在Jest中设置模拟日期?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！