反应打字稿测试 TypeError：MutationObserver 不是构造函数

Question

我create-react上周创建了一个 React 应用程序。

我有一个简单的表单，当我单击提交时会显示一条消息。

我想测试一下，这是我创建的测试SampleForm.test.tsx：

import React from "react";
import { render, fireEvent, screen, waitFor } from "@testing-library/react";
import SampleForm from "./SampleForm";
import "@testing-library/jest-dom/extend-expect"


test("renders submits form", async () => {
    const str = "THIS DIDNT DO ANYTHING";
    const { container, getByText, findByText } = render(<SampleForm />);

    fireEvent.click(screen.getByText("Submit"));

    await waitFor(() => expect(screen.getByText(str)))
});

我在 waitFor

类型错误：MutationObserver 不是构造函数

堆栈跟踪：

at node_modules/@testing-library/dom/dist/wait-for.js:38:22
      at waitFor (node_modules/@testing-library/dom/dist/wait-for.js:31:10)
      at node_modules/@testing-library/dom/dist/wait-for.js:70:54
      at node_modules/@testing-library/react/dist/pure.js:51:22
      at node_modules/@testing-library/react/dist/act-compat.js:60:24
      at batchedUpdates$1 (node_modules/react-dom/cjs/react-dom.development.js:21856:12)
      at act (node_modules/react-dom/cjs/react-dom-test-utils.development.js:929:14)
      at node_modules/@testing-library/react/dist/act-compat.js:59:20
      at asyncAct (node_modules/@testing-library/react/dist/act-compat.js:38:14)
      at Object.asyncWrapper (node_modules/@testing-library/react/dist/pure.js:50:35)
      at waitForWrapper (node_modules/@testing-library/dom/dist/wait-for.js:70:35)
      at Object.<anonymous> (src/components/SampleForm.test.tsx:18:11)

我尝试了几种不同的样式和文本查询更改。来自这里的样本

这是我试图开始工作的直接例子

我对添加垫片和旋转犹豫不决，因为根据示例我不应该做任何这些。我想了解为什么该示例不起作用。

我的package.json：

{
  "name": "intact",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@rjsf/core": "^2.0.0-alpha.6",
    "@testing-library/jest-dom": "^5.3.0",
    "@testing-library/react": "^10.0.2",
    "@testing-library/user-event": "^10.0.1",
    "@types/jest": "^25.1.5",
    "@types/lodash": "^4.14.149",
    "@types/react": "^16.9.0",
    "@types/react-dom": "^16.9.0",
    "@types/react-router-dom": "^5.1.3",
    "bootstrap": "^4.4.1",
    "lodash": "^4.17.15",
    "msal": "^1.2.2",
    "react": "^16.13.1",
    "react-aad-msal": "^2.3.4",
    "react-bootstrap": "^1.0.0",
    "react-dom": "^16.13.1",
    "react-router-dom": "^5.1.2",
    "react-scripts": "3.4.1",
    "typescript": "^3.8.3"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "devDependencies": {
    "@types/fs-extra": "^8.1.0",
    "@types/node": "^13.11.0",
    "@types/rimraf": "^3.0.0",
    "fs-extra": "^9.0.0",
    "rimraf": "^3.0.2",
    "ts-node": "^8.8.1"
  }
}

编辑：04-05-2020

Answer 1

你在运行最新的CRA吗？如果是这样，那么这个问题https://github.com/facebook/create-react-app/pull/8362可能就是您遇到的问题。这可以通过安装https://www.npmjs.com/package/jest-environment-jsdom-sixteen 来解决，例如$ yarn add -D jest-environment-jsdom-sixteen并编辑您的测试脚本：

 ...
  "scripts": {
    ...
-   "test": "react-scripts test --env=dom"
+   "test": "react-scripts test --env=jest-environment-jsdom-sixteen"
    ...
  },
  ...
  "devDependencies": {
    ...
    "jest-environment-jsdom-sixteen": "^1.0.3",
    ...
  },
  ...

基本上你会告诉你的笑话使用 jsdom v16 而不是 v15（Jest v25 的默认值）。

Answer 2

我也面临同样的问题。

在尝试接受的答案之前，我更新react-scripts到了版本4.0.1。

这解决了问题，因为react-scripts 4.0.1使用了 Jest 26.6.x。

因此，请先尝试升级react-scripts。