开玩笑未实现window.alert() [英] jest not implemented window.alert()

问题描述

我已经开玩笑地为我的api编写了测试.我在测试文件中添加了调用我的api的函数，如下所示:

i have written test for my api with jest . i added function that calls my api in test file as below:

import AuthManager from "../Client/Modules/Auth/AuthManager";

并按如下所示使用它:

test("login api resolves true", () => {
  return expect(AuthManager.login("test", "test")).resolves.toMatchObject(
    expect.objectContaining({
      accessToken: expect.any(String),
      email: expect.any(String),
      expiresIn: expect.any(Number),
      refreshToken: expect.any(String),
      userFullName: expect.any(String),
      userId: expect.any(Number)
    })
  );
});

我的测试通过了，但是出现如下错误:

my test passes but i have an error as below:

错误:未实现:window.alert

Error: Not implemented: window.alert

如何解决这个问题?

推荐答案

默认测试环境表示Jest是jsdom提供的类似浏览器的环境.

The default test environment for Jest is a browser-like environment provided by jsdom.

jsdom实现了实际浏览器将提供的大部分功能(包括全局window对象)，但并未实现所有功能.

jsdom implements most of what an actual browser would provide (including the global window object), but it doesn't implement everything.

专门针对这种情况，jsdom不实现window.alert，而是在调用它时抛出Error，如在源代码

Specifically for this case, jsdom does not implement window.alert, and instead throws an Error when it is called as can be seen in the source code here.

只要您知道代码为何启动alert的原因，并且知道测试在Error之外正常运行，则可以通过为window.alert提供空实现来抑制Error:

As long as you know why your code is launching the alert and know that your test is working properly aside from the Error then you can suppress the Error by providing an empty implementation for window.alert:

test("login api resolves true", () => {
  const jsdomAlert = window.alert;  // remember the jsdom alert
  window.alert = () => {};  // provide an empty implementation for window.alert
  return expect(AuthManager.login("test", "test")).resolves.toMatchObject(
    expect.objectContaining({
      accessToken: expect.any(String),
      email: expect.any(String),
      expiresIn: expect.any(Number),
      refreshToken: expect.any(String),
      userFullName: expect.any(String),
      userId: expect.any(Number)
    })
  );  // SUCCESS
  window.alert = jsdomAlert;  // restore the jsdom alert
});

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