mirror of
https://github.com/jaywcjlove/reference.git
synced 2025-06-17 20:51:21 +08:00
638 lines
132 KiB
HTML
638 lines
132 KiB
HTML
<!doctype html>
|
||
<html lang="en" data-color-mode="dark">
|
||
<head>
|
||
<meta charset="utf-8">
|
||
<title>Jest 备忘清单
|
||
& jest cheatsheet & Quick Reference</title>
|
||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||
<meta description="Jest 是一款优雅、简洁的 JavaScript 测试框架。为开发人员分享快速参考备忘单。">
|
||
<meta keywords="Quick,Reference,cheatsheet,jest">
|
||
<link rel="icon" href="data:image/svg+xml,%3Csvg%20viewBox%3D%220%200%2024%2024%22%20fill%3D%22none%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20height%3D%221em%22%20width%3D%221em%22%3E%20%3Cpath%20opacity%3D%22.4%22%20d%3D%22m21.66%2010.44-.98%204.18c-.84%203.61-2.5%205.07-5.62%204.77-.5-.04-1.04-.13-1.62-.27l-1.68-.4c-4.17-.99-5.46-3.05-4.48-7.23l.98-4.19c.2-.85.44-1.59.74-2.2%201.17-2.42%203.16-3.07%206.5-2.28l1.67.39c4.19.98%205.47%203.05%204.49%207.23Z%22%20fill%3D%22%23777%22%2F%3E%20%3Cpath%20d%3D%22M15.06%2019.39c-.62.42-1.4.77-2.35%201.08l-1.58.52c-3.97%201.28-6.06.21-7.35-3.76L2.5%2013.28c-1.28-3.97-.22-6.07%203.75-7.35l1.58-.52c.41-.13.8-.24%201.17-.31-.3.61-.54%201.35-.74%202.2l-.98%204.19c-.98%204.18.31%206.24%204.48%207.23l1.68.4c.58.14%201.12.23%201.62.27Zm2.43-8.88c-.06%200-.12-.01-.19-.02l-4.85-1.23a.75.75%200%200%201%20.37-1.45l4.85%201.23a.748.748%200%200%201-.18%201.47Z%22%20fill%3D%22%23999%22%20%2F%3E%20%3Cpath%20d%3D%22M14.56%2013.89c-.06%200-.12-.01-.19-.02l-2.91-.74a.75.75%200%200%201%20.37-1.45l2.91.74c.4.1.64.51.54.91-.08.34-.38.56-.72.56Z%22%20fill%3D%22%23999%22%20%2F%3E%20%3C%2Fsvg%3E" type="image/svg+xml">
|
||
<link rel="stylesheet" href="../style/style.css">
|
||
</head>
|
||
<body><nav class="header-nav"><div class="max-container"><a href="../index.html" class="logo"><svg viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg" height="1em" width="1em">
|
||
<path opacity=".4" d="m21.66 10.44-.98 4.18c-.84 3.61-2.5 5.07-5.62 4.77-.5-.04-1.04-.13-1.62-.27l-1.68-.4c-4.17-.99-5.46-3.05-4.48-7.23l.98-4.19c.2-.85.44-1.59.74-2.2 1.17-2.42 3.16-3.07 6.5-2.28l1.67.39c4.19.98 5.47 3.05 4.49 7.23Z" fill="currentColor"></path>
|
||
<path d="M15.06 19.39c-.62.42-1.4.77-2.35 1.08l-1.58.52c-3.97 1.28-6.06.21-7.35-3.76L2.5 13.28c-1.28-3.97-.22-6.07 3.75-7.35l1.58-.52c.41-.13.8-.24 1.17-.31-.3.61-.54 1.35-.74 2.2l-.98 4.19c-.98 4.18.31 6.24 4.48 7.23l1.68.4c.58.14 1.12.23 1.62.27Zm2.43-8.88c-.06 0-.12-.01-.19-.02l-4.85-1.23a.75.75 0 0 1 .37-1.45l4.85 1.23a.748.748 0 0 1-.18 1.47Z" fill="currentColor"></path>
|
||
<path d="M14.56 13.89c-.06 0-.12-.01-.19-.02l-2.91-.74a.75.75 0 0 1 .37-1.45l2.91.74c.4.1.64.51.54.91-.08.34-.38.56-.72.56Z" fill="currentColor"></path>
|
||
</svg>
|
||
<span class="title">Quick Reference</span></a><div class="menu"><a href="https://github.com/jaywcjlove/reference/blob/main/docs/jest.md" class="" target="__blank"><svg viewBox="0 0 36 36" fill="currentColor" height="1em" width="1em"><path d="m33 6.4-3.7-3.7a1.71 1.71 0 0 0-2.36 0L23.65 6H6a2 2 0 0 0-2 2v22a2 2 0 0 0 2 2h22a2 2 0 0 0 2-2V11.76l3-3a1.67 1.67 0 0 0 0-2.36ZM18.83 20.13l-4.19.93 1-4.15 9.55-9.57 3.23 3.23ZM29.5 9.43 26.27 6.2l1.85-1.85 3.23 3.23Z"></path><path fill="none" d="M0 0h36v36H0z"></path></svg><span>编辑</span></a><button id="darkMode" type="button"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="currentColor" class="light" height="1em" width="1em">
|
||
<path d="M6.995 12c0 2.761 2.246 5.007 5.007 5.007s5.007-2.246 5.007-5.007-2.246-5.007-5.007-5.007S6.995 9.239 6.995 12zM11 19h2v3h-2zm0-17h2v3h-2zm-9 9h3v2H2zm17 0h3v2h-3zM5.637 19.778l-1.414-1.414 2.121-2.121 1.414 1.414zM16.242 6.344l2.122-2.122 1.414 1.414-2.122 2.122zM6.344 7.759 4.223 5.637l1.415-1.414 2.12 2.122zm13.434 10.605-1.414 1.414-2.122-2.122 1.414-1.414z"></path>
|
||
</svg>
|
||
<svg xmlns="http://www.w3.org/2000/svg" fill="currentColor" viewBox="0 0 24 24" class="dark" height="1em" width="1em">
|
||
<path d="M12 11.807A9.002 9.002 0 0 1 10.049 2a9.942 9.942 0 0 0-5.12 2.735c-3.905 3.905-3.905 10.237 0 14.142 3.906 3.906 10.237 3.905 14.143 0a9.946 9.946 0 0 0 2.735-5.119A9.003 9.003 0 0 1 12 11.807z"></path>
|
||
</svg>
|
||
</button><script>
|
||
const LOCAL_NANE = '_dark_mode_theme_'
|
||
const rememberedValue = localStorage.getItem(LOCAL_NANE);
|
||
if (rememberedValue && ['light', 'dark'].includes(rememberedValue)) {
|
||
document.documentElement.setAttribute('data-color-mode', rememberedValue);
|
||
}
|
||
const button = document.querySelector('#darkMode');
|
||
button.onclick = () => {
|
||
const theme = document.documentElement.dataset.colorMode;
|
||
const mode = theme === 'light' ? 'dark' : 'light';
|
||
document.documentElement.setAttribute('data-color-mode', mode);
|
||
localStorage.setItem(LOCAL_NANE, mode);
|
||
}
|
||
</script><a href="https://github.com/jaywcjlove/reference" class="" target="__blank"><svg viewBox="0 0 16 16" fill="currentColor" height="1em" width="1em"><path d="M8 0C3.58 0 0 3.58 0 8c0 3.54 2.29 6.53 5.47 7.59.4.07.55-.17.55-.38 0-.19-.01-.82-.01-1.49-2.01.37-2.53-.49-2.69-.94-.09-.23-.48-.94-.82-1.13-.28-.15-.68-.52-.01-.53.63-.01 1.08.58 1.23.82.72 1.21 1.87.87 2.33.66.07-.52.28-.87.51-1.07-1.78-.2-3.64-.89-3.64-3.95 0-.87.31-1.59.82-2.15-.08-.2-.36-1.02.08-2.12 0 0 .67-.21 2.2.82.64-.18 1.32-.27 2-.27.68 0 1.36.09 2 .27 1.53-1.04 2.2-.82 2.2-.82.44 1.1.16 1.92.08 2.12.51.56.82 1.27.82 2.15 0 3.07-1.87 3.75-3.65 3.95.29.25.54.73.54 1.48 0 1.07-.01 1.93-.01 2.2 0 .21.15.46.55.38A8.012 8.012 0 0 0 16 8c0-4.42-3.58-8-8-8z"></path></svg></a></div></div></nav><div class="wrap max-container"><header class="wrap-header h1wrap"><h1 id="jest-备忘清单"><a aria-hidden="true" tabindex="-1" href="#jest-备忘清单"><span class="icon icon-link"></span></a>Jest 备忘清单</h1><div class="wrap-body">
|
||
<p>Jest 是一款优雅、简洁的 JavaScript 测试框架。</p>
|
||
</div></header><div class="h1wrap-body"><div class="wrap"><div class="wrap-header h2wrap"><h2 id="入门"><a aria-hidden="true" tabindex="-1" href="#入门"><span class="icon icon-link"></span></a>入门</h2><div class="wrap-body">
|
||
<!--rehype:body-class=cols-6-->
|
||
</div></div><div class="h2wrap-body cols-6"><div class="wrap col-span-2 row-span-2"><div class="wrap-header h3wrap"><h3 id="介绍"><a aria-hidden="true" tabindex="-1" href="#介绍"><span class="icon icon-link"></span></a>介绍</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=col-span-2 row-span-2-->
|
||
<p><a href="https://jestjs.io/">Jest</a> 是一款优雅、简洁的 JavaScript 测试框架。</p>
|
||
<ul>
|
||
<li><code>无需配置</code> 大多数 JS 项目中即装即用，无需配置</li>
|
||
<li><code>优秀接口</code> 从 <code>it</code> 到 <code>expect</code> - Jest 将工具包整合在一处。文档齐全、不断维护，非常不错。</li>
|
||
<li><code>隔离的</code> 并行进行测试，发挥每一丝算力。</li>
|
||
<li><code>快照</code> 轻松编写持续追踪大型对象的测试，并在测试旁或代码内显示实时快照。</li>
|
||
<li><code>代码覆盖</code> 无需其他操作，您仅需添加 <code>--coverage</code> 参数来生成代码覆盖率报告。</li>
|
||
</ul>
|
||
</div></div></div><div class="wrap col-span-2 row-span-2"><div class="wrap-header h3wrap"><h3 id="快速开始"><a aria-hidden="true" tabindex="-1" href="#快速开始"><span class="icon icon-link"></span></a>快速开始</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=col-span-2 row-span-2-->
|
||
<pre class="language-bash"><code class="language-bash code-highlight"><span class="code-line"><span class="token function">npm</span> <span class="token function">install</span> --save-dev jest
|
||
</span></code></pre>
|
||
<p>Add to <code>package.json</code></p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token string-property property">"scripts"</span><span class="token operator">:</span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token string-property property">"test"</span><span class="token operator">:</span> <span class="token string">"jest"</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span>
|
||
</span></code></pre>
|
||
<p>运行你的测试</p>
|
||
<pre class="language-bash"><code class="language-bash code-highlight"><span class="code-line"><span class="token function">npm</span> <span class="token builtin class-name">test</span> -- <span class="token parameter variable">--watch</span>
|
||
</span></code></pre>
|
||
<p>查看: <a href="https://jestjs.io/docs/getting-started">Getting started</a></p>
|
||
</div></div></div><div class="wrap col-span-2"><div class="wrap-header h3wrap"><h3 id="编写测试"><a aria-hidden="true" tabindex="-1" href="#编写测试"><span class="icon icon-link"></span></a>编写测试</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=col-span-2-->
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">describe</span><span class="token punctuation">(</span><span class="token string">'My work'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'works'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap col-span-2"><div class="wrap-header h3wrap"><h3 id="bdd-语法"><a aria-hidden="true" tabindex="-1" href="#bdd-语法"><span class="icon icon-link"></span></a>BDD 语法</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=col-span-2-->
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">describe</span><span class="token punctuation">(</span><span class="token string">'My work'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line highlight-line"> <span class="token function">it</span><span class="token punctuation">(</span><span class="token string">'works'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span> <span class="token comment">// `it`是`test`的别名</span>
|
||
</span><span class="code-line"> ···
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap col-span-3 row-span-2"><div class="wrap-header h3wrap"><h3 id="测试结构"><a aria-hidden="true" tabindex="-1" href="#测试结构"><span class="icon icon-link"></span></a>测试结构</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=col-span-3 row-span-2-->
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">describe</span><span class="token punctuation">(</span><span class="token string">'makePoniesPink'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token function">beforeAll</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">/* 在所有测试之前运行 */</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">afterAll</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">/* 在所有测试后运行 */</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">beforeEach</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">/* 在每次测试之前运行 */</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">afterEach</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">/* 每次测试后运行 */</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'make each pony pink'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> actual <span class="token operator">=</span> <span class="token function">fn</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token string">'Alice'</span><span class="token punctuation">,</span> <span class="token string">'Bob'</span><span class="token punctuation">,</span> <span class="token string">'Eve'</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>actual<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token string">'Pink Alice'</span><span class="token punctuation">,</span> <span class="token string">'Pink Bob'</span><span class="token punctuation">,</span> <span class="token string">'Pink Eve'</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="聚焦测试"><a aria-hidden="true" tabindex="-1" href="#聚焦测试"><span class="icon icon-link"></span></a>聚焦测试</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">describe<span class="token punctuation">.</span><span class="token method function property-access">only</span><span class="token punctuation">(</span>···<span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line">it<span class="token punctuation">.</span><span class="token method function property-access">only</span><span class="token punctuation">(</span>···<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 别名: fit()</span>
|
||
</span></code></pre>
|
||
<p>查看: <a href="https://jestjs.io/docs/api#testonlyname-fn-timeout">test.only</a></p>
|
||
</div></div></div><div class="wrap col-span-2"><div class="wrap-header h3wrap"><h3 id="可选参数"><a aria-hidden="true" tabindex="-1" href="#可选参数"><span class="icon icon-link"></span></a>可选参数</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=col-span-2-->
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<table><thead><tr><th>Flag</th><th>Description</th></tr></thead><tbody><tr><td><code>--coverage</code></td><td>查看测试覆盖率摘要</td></tr><tr><td><code>--detectOpenHandles</code></td><td>查看未关闭端口的摘要</td></tr><tr><td><code>--runInBand</code></td><td>一个接一个地运行所有测试</td></tr><tr><td><code>--bail,-b</code></td><td>失败跳出测试</td></tr></tbody></table>
|
||
<p>更多参数查看 <a href="https://jestjs.io/docs/next/cli#--bailn">Jest CLI Options</a></p>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="跳过测试"><a aria-hidden="true" tabindex="-1" href="#跳过测试"><span class="icon icon-link"></span></a>跳过测试</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">describe<span class="token punctuation">.</span><span class="token method function property-access">skip</span><span class="token punctuation">(</span>···<span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line">it<span class="token punctuation">.</span><span class="token method function property-access">skip</span><span class="token punctuation">(</span>···<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 别名: xit()</span>
|
||
</span></code></pre>
|
||
<p>查看: <a href="https://jestjs.io/docs/next/api#testskipname-fn">test.skip</a></p>
|
||
</div></div></div><div class="wrap col-span-2"><div class="wrap-header h3wrap"><h3 id="基本测试用例"><a aria-hidden="true" tabindex="-1" href="#基本测试用例"><span class="icon icon-link"></span></a>基本测试用例</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=col-span-2-->
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token property-access">not</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">toBeTruthy</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// Errors 测试</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrow</span><span class="token punctuation">(</span>error<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">toThrowErrorMatchingSnapshot</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div></div></div><div class="wrap"><div class="wrap-header h2wrap"><h2 id="匹配器"><a aria-hidden="true" tabindex="-1" href="#匹配器"><span class="icon icon-link"></span></a>匹配器</h2><div class="wrap-body">
|
||
</div></div><div class="h2wrap-body"><div class="wrap"><div class="wrap-header h3wrap"><h3 id="基本匹配器"><a aria-hidden="true" tabindex="-1" href="#基本匹配器"><span class="icon icon-link"></span></a>基本匹配器</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">42</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token number">42</span><span class="token punctuation">)</span> <span class="token comment">// 严格相等 (===)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">42</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token property-access">not</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span> <span class="token comment">// 严格相等 (!==)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token comment">// 深度相等</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// 深度相等</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span> <span class="token keyword nil">undefined</span><span class="token punctuation">,</span> <span class="token literal-property property">b</span><span class="token operator">:</span> <span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">b</span><span class="token operator">:</span> <span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// 严格相等 (Jest 23+)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span> <span class="token keyword nil">undefined</span><span class="token punctuation">,</span> <span class="token literal-property property">b</span><span class="token operator">:</span> <span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token property-access">not</span><span class="token punctuation">.</span><span class="token method function property-access">toStrictEqual</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">b</span><span class="token operator">:</span> <span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p><a href="http://jestjs.io/docs/en/using-matchers">Using matchers</a>, <a href="https://jestjs.io/docs/en/expect">matchers docs</a></p>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="真实性"><a aria-hidden="true" tabindex="-1" href="#真实性"><span class="icon icon-link"></span></a>真实性</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 匹配 if 语句视为 true 的任何内容</span>
|
||
</span><span class="code-line"><span class="token comment">// （not false、0、''、null、undefined、NaN）</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token string">'foo'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeTruthy</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 匹配 if 语句视为 false 的任何内容</span>
|
||
</span><span class="code-line"><span class="token comment">// （false、0、''、null、undefined、NaN）</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token string">''</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeFalsy</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 仅匹配 null</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token keyword null nil">null</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeNull</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 仅匹配未定义</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token keyword nil">undefined</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeUndefined</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// toBeUndefined 的反义词</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">7</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeDefined</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 匹配真假</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Boolean</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="数字"><a aria-hidden="true" tabindex="-1" href="#数字"><span class="icon icon-link"></span></a>数字</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 大于</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeGreaterThan</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 大于或等于</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeGreaterThanOrEqual</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 小于</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeLessThan</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 小于或等于</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeLessThanOrEqual</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 接近于</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">0.2</span> <span class="token operator">+</span> <span class="token number">0.1</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeCloseTo</span><span class="token punctuation">(</span><span class="token number">0.3</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 原始值的传递类型</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token number">NaN</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Number</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="字符串"><a aria-hidden="true" tabindex="-1" href="#字符串"><span class="icon icon-link"></span></a>字符串</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 检查字符串是否与正则表达式匹配。</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token string">'long string'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatch</span><span class="token punctuation">(</span><span class="token string">'str'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token string">'string'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">String</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token string">'coffee'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatch</span><span class="token punctuation">(</span><span class="token regex"><span class="token regex-delimiter">/</span><span class="token regex-source language-regex">ff</span><span class="token regex-delimiter">/</span></span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token string">'pizza'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token property-access">not</span><span class="token punctuation">.</span><span class="token method function property-access">toMatch</span><span class="token punctuation">(</span><span class="token string">'coffee'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token string">'pizza'</span><span class="token punctuation">,</span> <span class="token string">'coffee'</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>
|
||
</span><span class="code-line"> <span class="token punctuation">[</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">stringContaining</span><span class="token punctuation">(</span><span class="token string">'zz'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">stringMatching</span><span class="token punctuation">(</span><span class="token regex"><span class="token regex-delimiter">/</span><span class="token regex-source language-regex">ff</span><span class="token regex-delimiter">/</span></span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">]</span>
|
||
</span><span class="code-line"><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="数组"><a aria-hidden="true" tabindex="-1" href="#数组"><span class="icon icon-link"></span></a>数组</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Array</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> exampleArray <span class="token operator">=</span> <span class="token punctuation">[</span>
|
||
</span><span class="code-line"> <span class="token string">'Alice'</span><span class="token punctuation">,</span> <span class="token string">'Bob'</span><span class="token punctuation">,</span> <span class="token string">'Eve'</span>
|
||
</span><span class="code-line"><span class="token punctuation">]</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>exampleArray<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveLength</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>exampleArray<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toContain</span><span class="token punctuation">(</span><span class="token string">'Alice'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>exampleArray<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">arrayContaining</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token string">'Alice'</span><span class="token punctuation">,</span> <span class="token string">'Bob'</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span> <span class="token number">1</span> <span class="token punctuation">}</span><span class="token punctuation">,</span> <span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span> <span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">toContainEqual</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span> <span class="token number">1</span> <span class="token punctuation">}</span><span class="token punctuation">)</span> <span class="token comment">// 包含相等</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="对象"><a aria-hidden="true" tabindex="-1" href="#对象"><span class="icon icon-link"></span></a>对象</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span><span class="token number">1</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveProperty</span><span class="token punctuation">(</span><span class="token string">'a'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span><span class="token number">1</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveProperty</span><span class="token punctuation">(</span><span class="token string">'a'</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span> <span class="token punctuation">{</span><span class="token literal-property property">b</span><span class="token operator">:</span><span class="token number">1</span><span class="token punctuation">}</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveProperty</span><span class="token punctuation">(</span><span class="token string">'a.b'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token literal-property property">b</span><span class="token operator">:</span><span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatchObject</span><span class="token punctuation">(</span><span class="token punctuation">{</span><span class="token literal-property property">a</span><span class="token operator">:</span><span class="token number">1</span><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token literal-property property">b</span><span class="token operator">:</span><span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatchObject</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token literal-property property">a</span><span class="token operator">:</span> expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Number</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"> <span class="token literal-property property">b</span><span class="token operator">:</span> expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Number</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span> <span class="token number">1</span> <span class="token punctuation">}</span><span class="token punctuation">,</span> <span class="token punctuation">{</span> <span class="token literal-property property">b</span><span class="token operator">:</span> <span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span><span class="token punctuation">[</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">objectContaining</span><span class="token punctuation">(</span>
|
||
</span><span class="code-line"> <span class="token punctuation">{</span> <span class="token literal-property property">a</span><span class="token operator">:</span> expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Number</span><span class="token punctuation">)</span> <span class="token punctuation">}</span>
|
||
</span><span class="code-line"> <span class="token punctuation">)</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">anything</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"><span class="token punctuation">]</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap row-span-2"><div class="wrap-header h3wrap"><h3 id="模拟函数"><a aria-hidden="true" tabindex="-1" href="#模拟函数"><span class="icon icon-link"></span></a>模拟函数</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// const fn = jest.fn()</span>
|
||
</span><span class="code-line"><span class="token comment">// const fn = jest.fn().mockName('Unicorn') -- 命名为 mock, Jest 22+</span>
|
||
</span><span class="code-line"><span class="token comment">// 函数被调用</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeCalled</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 函数*未*调用</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token property-access">not</span><span class="token punctuation">.</span><span class="token method function property-access">toBeCalled</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 函数只被调用一次</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveBeenCalledTimes</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 任何执行都带有这些参数</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeCalledWith</span><span class="token punctuation">(</span>arg1<span class="token punctuation">,</span> arg2<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 最后一个执行是用这些参数</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveBeenLastCalledWith</span><span class="token punctuation">(</span>arg1<span class="token punctuation">,</span> arg2<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 第 N 个执行带有这些参数（Jest 23+）</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveBeenNthCalledWith</span><span class="token punctuation">(</span>callNumber<span class="token punctuation">,</span> args<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 函数返回没有抛出错误（Jest 23+）</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveReturnedTimes</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 函数返回一个值（Jest 23+）</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveReturnedWith</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 最后一个函数调用返回一个值（Jest 23+）</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveLastReturnedWith</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 第 N 个函数调用返回一个值（Jest 23+）</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveNthReturnedWith</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">.</span><span class="token property-access">mock</span><span class="token punctuation">.</span><span class="token property-access">calls</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span><span class="token punctuation">[</span>
|
||
</span><span class="code-line"> <span class="token punctuation">[</span><span class="token string">'first'</span><span class="token punctuation">,</span> <span class="token string">'call'</span><span class="token punctuation">,</span> <span class="token string">'args'</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"> <span class="token punctuation">[</span><span class="token string">'second'</span><span class="token punctuation">,</span> <span class="token string">'call'</span><span class="token punctuation">,</span> <span class="token string">'args'</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token comment">// 多次调用</span>
|
||
</span><span class="code-line"><span class="token comment">// fn.mock.calls[0][0] — 第一次调用的第一个参数</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">.</span><span class="token property-access">mock</span><span class="token punctuation">.</span><span class="token property-access">calls</span><span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div><div class="h3wrap-body"><div class="wrap"><div class="wrap-header h4wrap"><h4 id="别名"><a aria-hidden="true" tabindex="-1" href="#别名"><span class="icon icon-link"></span></a>别名</h4><div class="wrap-body">
|
||
<ul>
|
||
<li><code>toBeCalled</code> → <code>toHaveBeenCalled</code></li>
|
||
<li><code>toBeCalledWith</code> → <code>toHaveBeenCalledWith</code></li>
|
||
<li><code>lastCalledWith</code> → <code>toHaveBeenLastCalledWith</code></li>
|
||
<li><code>nthCalledWith</code> → <code>toHaveBeenNthCalledWith</code></li>
|
||
<li><code>toReturnTimes</code> → <code>toHaveReturnedTimes</code></li>
|
||
<li><code>toReturnWith</code> → <code>toHaveReturnedWith</code></li>
|
||
<li><code>lastReturnedWith</code> → <code>toHaveLastReturnedWith</code></li>
|
||
<li><code>nthReturnedWith</code> → <code>toHaveNthReturnedWith</code></li>
|
||
</ul>
|
||
</div></div></div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="杂项"><a aria-hidden="true" tabindex="-1" href="#杂项"><span class="icon icon-link"></span></a>杂项</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 检查对象是否是类的实例。</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">A</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeInstanceOf</span><span class="token punctuation">(</span><span class="token constant">A</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// 检查对象是否是函数的实例。</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span><span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Function</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// 匹配除 null 或 undefined 之外的任何内容</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token string">'pizza'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span>expect<span class="token punctuation">.</span><span class="token method function property-access">anything</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="快照"><a aria-hidden="true" tabindex="-1" href="#快照"><span class="icon icon-link"></span></a>快照</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 这可确保某个值与最近的快照匹配。</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>node<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatchSnapshot</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// Jest 23+</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>user<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatchSnapshot</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token literal-property property">date</span><span class="token operator">:</span> expect<span class="token punctuation">.</span><span class="token method function property-access">any</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Date</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// 确保值与最近的快照匹配。</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>user<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatchInlineSnapshot</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="promise-匹配器jest-20"><a aria-hidden="true" tabindex="-1" href="#promise-匹配器jest-20"><span class="icon icon-link"></span></a>Promise 匹配器（Jest 20+）</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'resolve to lemon'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">// 验证在测试期间是否调用了一定数量的断言。</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">assertions</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 确保添加return语句</span>
|
||
</span><span class="code-line"> <span class="token keyword control-flow">return</span> <span class="token function">expect</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Promise</span><span class="token punctuation">.</span><span class="token method function property-access">resolve</span><span class="token punctuation">(</span><span class="token string">'lemon'</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token property-access">resolves</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token string">'lemon'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"> <span class="token keyword control-flow">return</span> <span class="token function">expect</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Promise</span><span class="token punctuation">.</span><span class="token method function property-access">reject</span><span class="token punctuation">(</span><span class="token string">'octopus'</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token property-access">rejects</span><span class="token punctuation">.</span><span class="token method function property-access">toBeDefined</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"> <span class="token keyword control-flow">return</span> <span class="token function">expect</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Promise</span><span class="token punctuation">.</span><span class="token method function property-access">reject</span><span class="token punctuation">(</span>
|
||
</span><span class="code-line"> <span class="token known-class-name class-name">Error</span><span class="token punctuation">(</span><span class="token string">'pizza'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token property-access">rejects</span><span class="token punctuation">.</span><span class="token method function property-access">toThrow</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>或者使用 async/await:</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'resolve to lemon'</span><span class="token punctuation">,</span> <span class="token keyword">async</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">assertions</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token keyword control-flow">await</span> <span class="token function">expect</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Promise</span><span class="token punctuation">.</span><span class="token method function property-access">resolve</span><span class="token punctuation">(</span><span class="token string">'lemon'</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token property-access">resolves</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token string">'lemon'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"> <span class="token keyword control-flow">await</span> <span class="token function">expect</span><span class="token punctuation">(</span><span class="token known-class-name class-name">Promise</span><span class="token punctuation">.</span><span class="token method function property-access">resolve</span><span class="token punctuation">(</span><span class="token string">'lemon'</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token property-access">resolves</span><span class="token punctuation">.</span><span class="token property-access">not</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token string">'octopus'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p><a href="https://jestjs.io/docs/en/expect#resolves">resolves 文档</a></p>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="例外"><a aria-hidden="true" tabindex="-1" href="#例外"><span class="icon icon-link"></span></a>例外</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// const fn = () => {</span>
|
||
</span><span class="code-line"><span class="token comment">// throw new Error('Out of cheese!')</span>
|
||
</span><span class="code-line"><span class="token comment">// }</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrow</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrow</span><span class="token punctuation">(</span><span class="token string">'Out of cheese'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// 测试错误消息在某处说“cheese”：这些是等价的</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrowError</span><span class="token punctuation">(</span><span class="token regex"><span class="token regex-delimiter">/</span><span class="token regex-source language-regex">cheese</span><span class="token regex-delimiter">/</span></span><span class="token punctuation">)</span><span class="token punctuation">;</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrowError</span><span class="token punctuation">(</span><span class="token string">'cheese'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// 测试准确的错误信息</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrowError</span><span class="token punctuation">(</span>
|
||
</span><span class="code-line"> <span class="token regex"><span class="token regex-delimiter">/</span><span class="token regex-source language-regex"><span class="token anchor function">^</span>Out of cheese!<span class="token anchor function">$</span></span><span class="token regex-delimiter">/</span></span>
|
||
</span><span class="code-line"><span class="token punctuation">)</span><span class="token punctuation">;</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrowError</span><span class="token punctuation">(</span>
|
||
</span><span class="code-line"> <span class="token keyword">new</span> <span class="token class-name">Error</span><span class="token punctuation">(</span><span class="token string">'Out of cheese!'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">)</span><span class="token punctuation">;</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"><span class="token comment">// 测试函数在调用时是否抛出与最新快照匹配的错误。</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrowErrorMatchingSnapshot</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div><div class="h3wrap-body"><div class="wrap"><div class="wrap-header h4wrap"><h4 id="别名-1"><a aria-hidden="true" tabindex="-1" href="#别名-1"><span class="icon icon-link"></span></a>别名</h4><div class="wrap-body">
|
||
<ul>
|
||
<li><code>toThrowError</code> → <code>toThrow</code></li>
|
||
</ul>
|
||
</div></div></div></div></div></div></div><div class="wrap"><div class="wrap-header h2wrap"><h2 id="异步测试"><a aria-hidden="true" tabindex="-1" href="#异步测试"><span class="icon icon-link"></span></a>异步测试</h2><div class="wrap-body">
|
||
</div></div><div class="h2wrap-body"><div class="wrap row-span-2"><div class="wrap-header h3wrap"><h3 id="实例"><a aria-hidden="true" tabindex="-1" href="#实例"><span class="icon icon-link"></span></a>实例</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<p>请参阅 Jest 文档中的 <a href="https://jestjs.io/docs/en/tutorial-async">更多示例</a>。</p>
|
||
<p>在异步测试中指定一些预期的断言是一个很好的做法，所以如果你的断言根本没有被调用，测试将会失败。</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'async test'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">// 在测试期间恰好调用了三个断言</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">assertions</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 或者 - 在测试期间至少调用一个断言</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">hasAssertions</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 你的异步测试</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>请注意，您也可以在任何 <code>describe</code> 和 <code>test</code> 之外对每个文件执行此操作：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">beforeEach</span><span class="token punctuation">(</span>expect<span class="token punctuation">.</span><span class="token property-access">hasAssertions</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>这将验证每个测试用例至少存在一个断言。 它还可以与更具体的 <code>expect.assertions(3)</code> 声明配合使用。</p>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="asyncawait"><a aria-hidden="true" tabindex="-1" href="#asyncawait"><span class="icon icon-link"></span></a>async/await</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'async test'</span><span class="token punctuation">,</span> <span class="token keyword">async</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">assertions</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"> <span class="token keyword">const</span> result <span class="token operator">=</span> <span class="token keyword control-flow">await</span> <span class="token function">runAsyncOperation</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>result<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap row-span-2"><div class="wrap-header h3wrap"><h3 id="done-回调"><a aria-hidden="true" tabindex="-1" href="#done-回调"><span class="icon icon-link"></span></a>done() 回调</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'async test'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token parameter">done</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">assertions</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"> <span class="token function">runAsyncOperation</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"> <span class="token function">setTimeout</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token keyword control-flow">try</span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> result <span class="token operator">=</span> <span class="token function">getAsyncOperationResult</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>result<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">done</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span> <span class="token keyword control-flow">catch</span> <span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> done<span class="token punctuation">.</span><span class="token method function property-access">fail</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>将断言包装在 <code>try/catch</code> 块中，否则 <code>Jest</code> 将忽略失败</p>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="promises"><a aria-hidden="true" tabindex="-1" href="#promises"><span class="icon icon-link"></span></a>Promises</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'async test'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> expect<span class="token punctuation">.</span><span class="token method function property-access">assertions</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">
|
||
</span><span class="code-line"> <span class="token keyword control-flow">return</span> <span class="token function">runAsyncOperation</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">then</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token parameter">result</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>result<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>从你的测试中 <em>返回</em> 一个 <code>Promise</code></p>
|
||
</div></div></div></div></div><div class="wrap"><div class="wrap-header h2wrap"><h2 id="模拟"><a aria-hidden="true" tabindex="-1" href="#模拟"><span class="icon icon-link"></span></a>模拟</h2><div class="wrap-body">
|
||
</div></div><div class="h2wrap-body"><div class="wrap row-span-2"><div class="wrap-header h3wrap"><h3 id="模拟函数-1"><a aria-hidden="true" tabindex="-1" href="#模拟函数-1"><span class="icon icon-link"></span></a>模拟函数</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'call the callback'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> callback <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">fn</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBeCalled</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>callback<span class="token punctuation">.</span><span class="token property-access">mock</span><span class="token punctuation">.</span><span class="token property-access">calls</span><span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">.</span><span class="token property-access">baz</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span><span class="token string">'pizza'</span><span class="token punctuation">)</span> <span class="token comment">// 第一次调用的第二个参数</span>
|
||
</span><span class="code-line"> <span class="token comment">// 匹配第一个和最后一个参数，但忽略第二个参数</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveBeenLastCalledWith</span><span class="token punctuation">(</span><span class="token string">'meal'</span><span class="token punctuation">,</span> expect<span class="token punctuation">.</span><span class="token method function property-access">anything</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token string">'margarita'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>您还可以使用快照：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'call the callback'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">// mockName 在 Jest 22+ 中可用</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> callback <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockName</span><span class="token punctuation">(</span><span class="token string">'Unicorn'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">fn</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatchSnapshot</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// -></span>
|
||
</span><span class="code-line"> <span class="token comment">// [MockFunction Unicorn] {</span>
|
||
</span><span class="code-line"> <span class="token comment">// "calls": Array [</span>
|
||
</span><span class="code-line"> <span class="token comment">// ...</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>并将实现传递给 <code>jest.fn</code> 函数：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> callback <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p><a href="https://jestjs.io/docs/en/mock-function-api">模拟函数文档</a></p>
|
||
</div></div></div><div class="wrap row-span-2"><div class="wrap-header h3wrap"><h3 id="返回解析和拒绝值"><a aria-hidden="true" tabindex="-1" href="#返回解析和拒绝值"><span class="icon icon-link"></span></a>返回、解析和拒绝值</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<p>您的模拟可以返回值：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> callback
|
||
</span><span class="code-line"> <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockReturnValue</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> callbackOnce
|
||
</span><span class="code-line"> <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockReturnValueOnce</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>或解析值：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> promise
|
||
</span><span class="code-line"> <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockResolvedValue</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> promiseOnce
|
||
</span><span class="code-line"> <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockResolvedValueOnce</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>他们甚至可以拒绝值：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> failedPromise
|
||
</span><span class="code-line"> <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockRejectedValue</span><span class="token punctuation">(</span><span class="token string">'Error'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> failedPromiseOnce
|
||
</span><span class="code-line"> <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockRejectedValueOnce</span><span class="token punctuation">(</span><span class="token string">'Error'</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>你甚至可以结合这些：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> callback
|
||
</span><span class="code-line"> <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockReturnValueOnce</span><span class="token punctuation">(</span><span class="token boolean">false</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockReturnValue</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// -></span>
|
||
</span><span class="code-line"><span class="token comment">// call 1: false</span>
|
||
</span><span class="code-line"><span class="token comment">// call 2+: true</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="使用-jestmock-方法模拟模块"><a aria-hidden="true" tabindex="-1" href="#使用-jestmock-方法模拟模块"><span class="icon icon-link"></span></a>使用 <code>jest.mock</code> 方法模拟模块</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">mock</span><span class="token punctuation">(</span><span class="token string">'lodash/memoize'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">(</span><span class="token parameter">a</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> a<span class="token punctuation">)</span> <span class="token comment">// The original lodash/memoize should exist</span>
|
||
</span><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">mock</span><span class="token punctuation">(</span><span class="token string">'lodash/memoize'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">(</span><span class="token parameter">a</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> a<span class="token punctuation">,</span> <span class="token punctuation">{</span> <span class="token literal-property property">virtual</span><span class="token operator">:</span> <span class="token boolean">true</span> <span class="token punctuation">}</span><span class="token punctuation">)</span> <span class="token comment">// The original lodash/memoize isn’t required</span>
|
||
</span></code></pre>
|
||
<p><a href="https://jestjs.io/docs/en/jest-object#jestmockmodulename-factory-options">jest.mock docs</a></p>
|
||
<blockquote>
|
||
<p>注意：当使用 <code>babel-jest</code> 时，对 <code>jest.mock</code> 的调用将自动提升到代码块的顶部。 如果您想明确避免这种行为，请使用 <code>jest.doMock</code>。</p>
|
||
</blockquote>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="使用模拟文件模拟模块"><a aria-hidden="true" tabindex="-1" href="#使用模拟文件模拟模块"><span class="icon icon-link"></span></a>使用模拟文件模拟模块</h3><div class="wrap-body">
|
||
<p>创建一个类似 <code>__mocks__/lodash/memoize.js</code> 的文件：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">module<span class="token punctuation">.</span><span class="token method-variable function-variable method function property-access">exports</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token parameter">a</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> a
|
||
</span></code></pre>
|
||
<p>添加到您的测试中：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">mock</span><span class="token punctuation">(</span><span class="token string">'lodash/memoize'</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>注意：当使用 <code>babel-jest</code> 时，对 <code>jest.mock</code> 的调用将自动提升到代码块的顶部。 如果您想明确避免这种行为，请使用 <code>jest.doMock</code>。</p>
|
||
<p><a href="https://jestjs.io/docs/en/manual-mocks">手动模拟文档</a></p>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="模拟对象方法"><a aria-hidden="true" tabindex="-1" href="#模拟对象方法"><span class="icon icon-link"></span></a>模拟对象方法</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> spy <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">spyOn</span><span class="token punctuation">(</span>console<span class="token punctuation">,</span> <span class="token string">'log'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockImplementation</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span><span class="token console class-name">console</span><span class="token punctuation">.</span><span class="token property-access">log</span><span class="token punctuation">.</span><span class="token property-access">mock</span><span class="token punctuation">.</span><span class="token property-access">calls</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toEqual</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token punctuation">[</span><span class="token string">'dope'</span><span class="token punctuation">]</span><span class="token punctuation">,</span> <span class="token punctuation">[</span><span class="token string">'nope'</span><span class="token punctuation">]</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">spy<span class="token punctuation">.</span><span class="token method function property-access">mockRestore</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> spy <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">spyOn</span><span class="token punctuation">(</span>ajax<span class="token punctuation">,</span> <span class="token string">'request'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">mockImplementation</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token known-class-name class-name">Promise</span><span class="token punctuation">.</span><span class="token method function property-access">resolve</span><span class="token punctuation">(</span><span class="token punctuation">{</span> <span class="token literal-property property">success</span><span class="token operator">:</span> <span class="token boolean">true</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">expect</span><span class="token punctuation">(</span>spy<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveBeenCalled</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line">spy<span class="token punctuation">.</span><span class="token method function property-access">mockRestore</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="模拟-getter-和-setter-jest-2210"><a aria-hidden="true" tabindex="-1" href="#模拟-getter-和-setter-jest-2210"><span class="icon icon-link"></span></a>模拟 getter 和 setter (Jest 22.1.0+)</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> <span class="token dom variable">location</span> <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> getTitle <span class="token operator">=</span> jest
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">spyOn</span><span class="token punctuation">(</span><span class="token dom variable">location</span><span class="token punctuation">,</span> <span class="token string">'title'</span><span class="token punctuation">,</span> <span class="token string">'get'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">mockImplementation</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token string">'pizza'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> setTitle <span class="token operator">=</span> jest
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">spyOn</span><span class="token punctuation">(</span><span class="token dom variable">location</span><span class="token punctuation">,</span> <span class="token string">'title'</span><span class="token punctuation">,</span> <span class="token string">'set'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token punctuation">.</span><span class="token method function property-access">mockImplementation</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap row-span-3"><div class="wrap-header h3wrap"><h3 id="定时器模拟"><a aria-hidden="true" tabindex="-1" href="#定时器模拟"><span class="icon icon-link"></span></a>定时器模拟</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-3-->
|
||
<p>为使用本机计时器函数（<code>setTimeout</code>、<code>setInterval</code>、<code>clearTimeout</code>、<code>clearInterval</code>）的代码编写同步测试。</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 启用假计时器</span>
|
||
</span><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">useFakeTimers</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'kill the time'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> callback <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 运行一些使用 setTimeout 或 setInterval 的代码</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> actual <span class="token operator">=</span> <span class="token function">someFunctionThatUseTimers</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 快进直到所有定时器都执行完毕</span>
|
||
</span><span class="code-line"> jest<span class="token punctuation">.</span><span class="token method function property-access">runAllTimers</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 同步检查结果</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveBeenCalledTimes</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>或者使用 <a href="https://jestjs.io/docs/en/timer-mocks#advance-timers-by-time">advanceTimersByTime()</a> 按时间调整计时器：</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 启用假计时器</span>
|
||
</span><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">useFakeTimers</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'kill the time'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> callback <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 运行一些使用 setTimeout 或 setInterval 的代码</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> actual <span class="token operator">=</span> <span class="token function">someFunctionThatUseTimers</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 快进 250 毫秒</span>
|
||
</span><span class="code-line"> jest<span class="token punctuation">.</span><span class="token method function property-access">advanceTimersByTime</span><span class="token punctuation">(</span><span class="token number">250</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token comment">// 同步检查结果</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toHaveBeenCalledTimes</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p>对于特殊情况，请使用 <a href="https://jestjs.io/docs/en/timer-mocks#run-pending-timers">jest.runOnlyPendingTimers()</a>。</p>
|
||
<p><strong>注意：</strong> 您应该在测试用例中调用 <code>jest.useFakeTimers()</code> 以使用其他假计时器方法。</p>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="模拟-getters-和-setters"><a aria-hidden="true" tabindex="-1" href="#模拟-getters-和-setters"><span class="icon icon-link"></span></a>模拟 getters 和 setters</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> getTitle <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token string">'pizza'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> setTitle <span class="token operator">=</span> jest<span class="token punctuation">.</span><span class="token method function property-access">fn</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> <span class="token dom variable">location</span> <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
|
||
</span><span class="code-line"><span class="token known-class-name class-name">Object</span><span class="token punctuation">.</span><span class="token method function property-access">defineProperty</span><span class="token punctuation">(</span><span class="token dom variable">location</span><span class="token punctuation">,</span> <span class="token string">'title'</span><span class="token punctuation">,</span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token literal-property property">get</span><span class="token operator">:</span> getTitle<span class="token punctuation">,</span>
|
||
</span><span class="code-line"> <span class="token literal-property property">set</span><span class="token operator">:</span> setTitle<span class="token punctuation">,</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap row-span-2"><div class="wrap-header h3wrap"><h3 id="清除和恢复模拟"><a aria-hidden="true" tabindex="-1" href="#清除和恢复模拟"><span class="icon icon-link"></span></a>清除和恢复模拟</h3><div class="wrap-body">
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
<p>对于一个模拟</p>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 清除模拟使用日期</span>
|
||
</span><span class="code-line"><span class="token comment">// （fn.mock.calls、fn.mock.instances）</span>
|
||
</span><span class="code-line">fn<span class="token punctuation">.</span><span class="token method function property-access">mockClear</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 清除并删除任何模拟的返回值或实现</span>
|
||
</span><span class="code-line">fn<span class="token punctuation">.</span><span class="token method function property-access">mockReset</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 重置并恢复初始实现</span>
|
||
</span><span class="code-line">fn<span class="token punctuation">.</span><span class="token method function property-access">mockRestore</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<blockquote>
|
||
<p>注意：<code>mockRestore</code> 仅适用于由<code>jest.spyOn</code> 创建的模拟。对于所有模拟：</p>
|
||
</blockquote>
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token comment">// 清除所有 mock 的 </span>
|
||
</span><span class="code-line"><span class="token comment">// mock.calls、mock.instances、</span>
|
||
</span><span class="code-line"><span class="token comment">// mock.contexts 和 mock.results 属性。</span>
|
||
</span><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">clearAllMocks</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 重置所有模拟的状态。</span>
|
||
</span><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">resetAllMocks</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 将所有模拟恢复到其原始值。</span>
|
||
</span><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">restoreAllMocks</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="使用模拟时访问原始模块"><a aria-hidden="true" tabindex="-1" href="#使用模拟时访问原始模块"><span class="icon icon-link"></span></a>使用模拟时访问原始模块</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">jest<span class="token punctuation">.</span><span class="token method function property-access">mock</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 模拟模块</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> fs <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token comment">// 原始模块</span>
|
||
</span><span class="code-line"><span class="token keyword">const</span> fs <span class="token operator">=</span> require<span class="token punctuation">.</span><span class="token method function property-access">requireActual</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div></div></div><div class="wrap"><div class="wrap-header h2wrap"><h2 id="数据驱动测试jest-23"><a aria-hidden="true" tabindex="-1" href="#数据驱动测试jest-23"><span class="icon icon-link"></span></a>数据驱动测试（Jest 23+）</h2><div class="wrap-body">
|
||
</div></div><div class="h2wrap-body"><div class="wrap"><div class="wrap-header h3wrap"><h3 id="使用不同的数据运行相同的测试"><a aria-hidden="true" tabindex="-1" href="#使用不同的数据运行相同的测试"><span class="icon icon-link"></span></a>使用不同的数据运行相同的测试</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">test<span class="token punctuation">.</span><span class="token method function property-access">each</span><span class="token punctuation">(</span><span class="token punctuation">[</span>
|
||
</span><span class="code-line"> <span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"> <span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"> <span class="token punctuation">[</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
|
||
</span><span class="code-line"><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token string">'.add(%s, %s)'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token parameter">a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> expected</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>a <span class="token operator">+</span> b<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span>expected<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="使用模板文字相同"><a aria-hidden="true" tabindex="-1" href="#使用模板文字相同"><span class="icon icon-link"></span></a>使用模板文字相同</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">test<span class="token punctuation">.</span><span class="token property-access">each</span><span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">
|
||
</span></span></span><span class="code-line"><span class="token template-string"><span class="token string"> a | b | expected
|
||
</span></span></span><span class="code-line"><span class="token template-string"><span class="token string"> </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">1</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> | </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">1</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> | </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">2</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">
|
||
</span></span></span><span class="code-line"><span class="token template-string"><span class="token string"> </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">1</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> | </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">2</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> | </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">3</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">
|
||
</span></span></span><span class="code-line"><span class="token template-string"><span class="token string"> </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">2</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> | </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">1</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> | </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token number">3</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">
|
||
</span></span></span><span class="code-line"><span class="token template-string"><span class="token string"></span><span class="token template-punctuation string">`</span></span><span class="token punctuation">(</span><span class="token string">'returns $expected when $a is added $b'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token parameter"><span class="token punctuation">{</span> a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> expected <span class="token punctuation">}</span></span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>a <span class="token operator">+</span> b<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toBe</span><span class="token punctuation">(</span>expected<span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="或在describe级别"><a aria-hidden="true" tabindex="-1" href="#或在describe级别"><span class="icon icon-link"></span></a>或在“describe”级别</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">describe<span class="token punctuation">.</span><span class="token method function property-access">each</span><span class="token punctuation">(</span><span class="token punctuation">[</span>
|
||
</span><span class="code-line"> <span class="token punctuation">[</span><span class="token string">'mobile'</span><span class="token punctuation">]</span><span class="token punctuation">,</span> <span class="token punctuation">[</span><span class="token string">'tablet'</span><span class="token punctuation">]</span><span class="token punctuation">,</span> <span class="token punctuation">[</span><span class="token string">'desktop'</span><span class="token punctuation">]</span>
|
||
</span><span class="code-line"><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token string">'checkout flow on %s'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token parameter">viewport</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'displays success page'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">//</span>
|
||
</span><span class="code-line"> <span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p><a href="https://jestjs.io/docs/en/api#describeeachtablename-fn-timeout">describe.each()</a> 文档、<a href="https://jestjs.io/docs/en/api#testeachtablename-fn-timeout">test.each()</a> 文档</p>
|
||
</div></div></div></div></div><div class="wrap"><div class="wrap-header h2wrap"><h2 id="跳过测试-1"><a aria-hidden="true" tabindex="-1" href="#跳过测试-1"><span class="icon icon-link"></span></a>跳过测试</h2><div class="wrap-body">
|
||
<!--rehype:body-class=cols-2-->
|
||
</div></div><div class="h2wrap-body cols-2"><div class="wrap"><div class="wrap-header h3wrap"><h3 id="不要运行这些测试"><a aria-hidden="true" tabindex="-1" href="#不要运行这些测试"><span class="icon icon-link"></span></a>不要运行这些测试</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">describe<span class="token punctuation">.</span><span class="token method function property-access">skip</span><span class="token punctuation">(</span><span class="token string">'makePoniesPink'</span><span class="token spread operator">...</span>
|
||
</span><span class="code-line">tests<span class="token punctuation">.</span><span class="token method function property-access">skip</span><span class="token punctuation">(</span><span class="token string">'make each pony pink'</span><span class="token spread operator">...</span>
|
||
</span></code></pre>
|
||
</div></div></div><div class="wrap"><div class="wrap-header h3wrap"><h3 id="仅运行以下测试"><a aria-hidden="true" tabindex="-1" href="#仅运行以下测试"><span class="icon icon-link"></span></a>仅运行以下测试</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line">describe<span class="token punctuation">.</span><span class="token method function property-access">only</span><span class="token punctuation">(</span><span class="token string">'makePoniesPink'</span><span class="token spread operator">...</span>
|
||
</span><span class="code-line">tests<span class="token punctuation">.</span><span class="token method function property-access">only</span><span class="token punctuation">(</span><span class="token string">'make each pony pink'</span><span class="token spread operator">...</span>
|
||
</span></code></pre>
|
||
</div></div></div></div></div><div class="wrap"><div class="wrap-header h2wrap"><h2 id="测试有副作用的模块"><a aria-hidden="true" tabindex="-1" href="#测试有副作用的模块"><span class="icon icon-link"></span></a>测试有副作用的模块</h2><div class="wrap-body">
|
||
<!--rehype:body-class=cols-1-->
|
||
</div></div><div class="h2wrap-body cols-1"><div class="wrap"><div class="wrap-header h3wrap"><h3 id="实例-1"><a aria-hidden="true" tabindex="-1" href="#实例-1"><span class="icon icon-link"></span></a>实例</h3><div class="wrap-body">
|
||
<pre class="language-js"><code class="language-js code-highlight"><span class="code-line"><span class="token keyword">const</span> modulePath <span class="token operator">=</span> <span class="token string">'../module-to-test'</span>
|
||
</span><span class="code-line"><span class="token function">afterEach</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> jest<span class="token punctuation">.</span><span class="token method function property-access">resetModules</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'第一次测试'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">// 准备第一次测试的条件</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> result <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span>modulePath<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>result<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toMatchSnapshot</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">'第二个文本'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token punctuation">{</span>
|
||
</span><span class="code-line"> <span class="token comment">// 准备第二次测试的条件</span>
|
||
</span><span class="code-line"> <span class="token keyword">const</span> <span class="token function-variable function">fn</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=></span> <span class="token function">require</span><span class="token punctuation">(</span>modulePath<span class="token punctuation">)</span>
|
||
</span><span class="code-line"> <span class="token function">expect</span><span class="token punctuation">(</span>fn<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token method function property-access">toThrow</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
|
||
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">)</span>
|
||
</span></code></pre>
|
||
<p><code>Node.js</code> 和 <code>Jest</code> 会缓存你需要的模块。 要测试具有副作用的模块，您需要在测试之间重置模块注册表</p>
|
||
</div></div></div></div></div><div class="wrap"><div class="wrap-header h2wrap"><h2 id="另见"><a aria-hidden="true" tabindex="-1" href="#另见"><span class="icon icon-link"></span></a>另见</h2><div class="wrap-body">
|
||
<ul>
|
||
<li><a href="https://github.com/sapegin/jest-cheat-sheet">Jest cheat sheet</a> <em>(github.com)</em></li>
|
||
</ul>
|
||
</div></div></div></div></div><footer class="footer-wrap"><footer class="max-container">© 2022 Kenny Wang, All rights reserved.</footer></footer></body>
|
||
</html>
|