.toBe 不是函数

Question

我创建了一个反应打字稿应用程序npx create-react-app . --template typescript

我添加了一个基本测试文件

import '@testing-library/jest-dom/extend-expect'

const sumPositiveNumbers = (num1:number, num2: number) => {
    return num1 + num2
}

describe('when test pass', () => {

    test('should return an answer', () => {
        expect(sumPositiveNumbers(4,5).toBe(9))
    })

})

我收到错误

TypeError: sumPositiveNumbers(...).toBe is not a function

package.json 看起来像

{
  "name": "test",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.11.4",
    "@testing-library/react": "^11.1.0",
    "@testing-library/user-event": "^12.1.10",
    "@types/jest": "^26.0.15",
    "@types/node": "^12.0.0",
    "@types/react": "^16.9.53",
    "@types/react-dom": "^16.9.8",
    "react": "^17.0.1",
    "react-dom": "^17.0.1",
    "react-scripts": "4.0.1",
    "typescript": "^4.0.3",
    "web-vitals": "^0.2.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }
}
    

我错过了什么，我做错了什么

我不断收到这样的错误，但我正在使用我认为可以工作的 create-react-app

Answer 1

您的右括号位于错误的位置。它应该是：

expect(sumPositiveNumbers(4,5)).toBe(9)