December 2017
Intermediate to advanced
329 pages
6h 9m
Chinese
Content preview from React学习手册
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238
｜
第
10
章
我们通过
storeFactory
创建了一个新的
Store
实例来配置该测试的，该
Store
中的
State
包含三种示例颜色。接下来，我们分发了
Action
生成器
addColor
添加了第
4
种颜色到
State
中：深蓝色。现在每个测试都会对分发的
Action
进行验证。每个测试中都包含一
个
expect
语句。如果其中任意一个测试未能成功执行，我们将会确切地知道是哪个新
的
Action
出了问题。
这次我们会使用两个新的匹配器：
.toBe
和
.toBeDefined
。
.toBe
匹配器会使用操作
符
===
比较结果。该匹配器还可以用来比较诸如数字或者字符串这类基元类型，
而
.toEqual
匹配器可以用于深入比较对象。
.toBeDefined
匹配器可以用来检查现变量或者函数的存在性。在这个测试中，我们会
检查是否存在时间戳。
这些测试可以验证我们的
Store
是否可以使用
Action
生成器添加新的颜色。这可以提高
我们对
Store
部分程序代码的信心，它能够正常工作。
测试
React
组件
React
组件为
React
提供了一组在创建和管理
DOM
时所需的指令集。我们可以通过渲染
和检查最终的
DOM
来测试这些组件。
我们并没有在浏览器中运行测试代码，而是在一个
Node.js
终端上运行的。
Node.js
并
没有为每个浏览器标准的
DOM API
提供支持。
jest
集成了一个名为
jsdom
的
npm
软件
包，它可以用于在
Node.js
中模拟浏览器环境，这对于测试
React
组件至关重要。
配置
jest
环境
jest
为用户提供了在运行任何测试代码之前运行脚本的能力，我们可以在其中设置额 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.