[英]How to isolate tests in React Testing Library?
My tests are affecting each other.我的测试相互影响。 I'm using the default create-react-app setup with Typescript.
我在 Typescript 中使用默认的 create-react-app 设置。 All tests run fine individually but when I run all tests the last one fails (both in IntelliJ and
npm test
).所有测试单独运行良好,但是当我运行所有测试时,最后一个失败(在 IntelliJ 和
npm test
)。 The assertion that fails finds a value that was caused by the previous test.失败的断言找到了由先前测试引起的值。
Now I have read articles such as Test Isolation with React but I am not sharing any values between my tests.现在我已经阅读了诸如Test Isolation with React 之类的文章,但我没有在我的测试之间共享任何值。 I also read about the cleanUp function and tried adding beforeEach(cleanup) and beforeAll(cleanUp), but I didn't found a working solution yet besides putting each test in a separate file.
我还阅读了 cleanUp 函数并尝试添加 beforeEach(cleanup) 和 beforeAll(cleanUp),但除了将每个测试放在单独的文件中之外,我还没有找到可行的解决方案。 I feel the solution should be pretty simple.
我觉得解决方案应该很简单。
I've quickly generated a create-react-app with TypeScript to reproduce the issue in a small as possible project: https://github.com/Leejjon/breakingtests我已经使用 TypeScript 快速生成了一个 create-react-app,以在一个尽可能小的项目中重现该问题: https : //github.com/Leejjon/breaktests
My App.tsx我的应用程序.tsx
import React from 'react';
import './App.css';
import {BrowserRouter, Link, Route} from 'react-router-dom';
const About: React.FC = () => {
return (
<div>
<h1 id="pageHeader">About page</h1>
<p>This is the about page</p>
</div>
);
};
const Home: React.FC = () => {
return (
<div>
<h1 id="pageHeader">Home page</h1>
<p>This is the home page</p>
</div>
);
};
const News: React.FC = () => {
return (
<div>
<h1 id="pageHeader">News page</h1>
<p>This is the news page</p>
</div>
);
};
const App: React.FC = () => {
return (
<div className="App">
<BrowserRouter>
<Link id="linkToHome" to="/">Home</Link><br/>
<Link id="linkToNews" to="/news">News</Link><br/>
<Link id="linkToAbout" to="/about">About</Link>
<Route exact path="/" component={Home}/>
<Route exact path="/news" component={News}/>
<Route exact path="/about" component={About}/>
</BrowserRouter>
</div>
);
};
export default App;
My App.test.tsx:我的 App.test.tsx:
import React from 'react';
import {render, fireEvent, waitForElement} from '@testing-library/react';
import App from './App';
describe('Test routing', () => {
test('Verify home page content', () => {
const {container} = render(<App/>);
const pageHeaderContent = container.querySelector("#pageHeader")
?.firstChild
?.textContent;
expect(pageHeaderContent).toMatch('Home page');
});
test('Navigate to news', async () => {
const {container} = render(<App/>);
const pageHeaderContent = container.querySelector("#pageHeader")
?.firstChild
?.textContent;
expect(pageHeaderContent).toMatch('Home page');
const linkToNewsElement: Element = (container.querySelector('#linkToNews') as Element);
fireEvent.click(linkToNewsElement);
const pageHeaderContentAfterClick = await waitForElement(() => container.querySelector('#pageHeader')?.firstChild?.textContent);
expect(pageHeaderContentAfterClick).toMatch('News page');
});
test('Navigate to about', async () => {
const {container} = render(<App/>);
const pageHeaderContent = container.querySelector("#pageHeader")
?.firstChild
?.textContent;
expect(pageHeaderContent).toMatch('Home page');
const linkToAboutElement: Element = (container.querySelector('#linkToAbout') as Element);
fireEvent.click(linkToAboutElement);
const pageHeaderContentAfterClick = await waitForElement(() => container.querySelector('#pageHeader')?.firstChild?.textContent);
expect(pageHeaderContentAfterClick).toMatch('About page');
});
});
I found out by adding console.log(document.location.href);
我通过添加
console.log(document.location.href);
that the location is not reset.该位置未重置。 Which makes sense.
这是有道理的。
The code below resets the url.下面的代码重置了 url。 I could enter any domain to fix my tests, for example
http://blabla/
will also work.我可以输入任何域来修复我的测试,例如
http://blabla/
也可以。
beforeEach(() => {
delete window.location;
// @ts-ignore
window.location = new URL('http://localhost/');
});
In TypeScript this gives an error: TS2739: Type 'URL' is missing the following properties from type 'Location': ancestorOrigins, assign, reload, replace
.在 TypeScript 中,这给出了一个错误:
TS2739: Type 'URL' is missing the following properties from type 'Location': ancestorOrigins, assign, reload, replace
。 I didn't know how to fix this so I suppressed it it for now.我不知道如何解决这个问题,所以我暂时压制了它。
EDIT:编辑:
cleanup Unmounts React trees that were mounted with render, but doesn't reset state from stores/reducers. cleanup 卸载与渲染一起安装的 React 树,但不会从商店/减速器重置状态。 The solution I took for this situation was to create a reset function in my store and call it at the beginning of each test.
我针对这种情况采取的解决方案是在我的商店中创建一个重置函数,并在每次测试开始时调用它。
resetStore: () => {
set(initialState);
},
and call it in your test file并在您的测试文件中调用它
beforeEach(() => {
resetStore();
});
If you're using mocha, Jest, or Jasmine, the cleanup will be done automatically, but you need to put your render
in a beforeEach
to recreate it for every test.如果您使用 mocha、Jest 或 Jasmine,清理将自动完成,但您需要将
render
放在beforeEach
中,以便为每个测试重新创建它。
let container;
beforeEach(() => {
const app = render(<App/>);
container = app.container
});
If you use another testing framework, you'll need to cleanup
manually like so如果您使用其他测试框架,则需要像这样手动
cleanup
import { cleanup, render } from '@testing-library/react'
import test from 'ava'
test.afterEach(cleanup)
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