Javascript测试单元,带有Jest和ES6模块

Question

谷歌搜索选择一个清晰和最新的解决方案时,有太多不同的帖子......

我写了3个测试来检查不同的可能性

===========.测试1确定================

// helloJest.js

function sayHello() {
  return "hello there jest"
}
module.exports = sayHello;

// helloJestTest

const sayHello = require('../../src/client/js/helloJest');
test('string returning hello there jest', () => {// 
  expect(sayHello()).toEqual('hello there jest');
});

===========.TEST 2 FAILING ================

// helloJest.js

function sayHello() {
  return "hello there jest"
}
export default { sayHello }; // <= changed

// helloJestTest

const sayHello = require('../../src/client/js/helloJest');
test('string returning hello there jest', () => {// 
  expect(sayHello()).toEqual('hello there jest');
});

TypeError: sayHello is not a function

      3 |
      4 | test('string returning hello there jest', () => {//
    > 5 |   expect(sayHello()).toEqual('hello there jest');
        |          ^
      6 | });
      7 |

===========.TEST 3 FAILING ================

// helloJest.js

function sayHello() {
  return "hello there jest"
}
export default { sayHello }; //  <= changed

// helloJestTest

import { sayHello } from '../../src/client/js/helloJest'; // <= changed
test('string returning hello there jest', () => {// 
  expect(sayHello()).toEqual('hello there jest');
});

    TypeError: (0 , _helloJest.sayHello) is not a function

      3 |
      4 | test('string returning hello there jest', () => {//
    > 5 |   expect(sayHello()).toEqual('hello there jest');
        |          ^
      6 | });

如何正确通过TEST 3 ???

我使用以下包

的package.json

"babel-core": "^6.26.3",
"babel-jest": "^23.6.0",
"babel-loader": "^7.1.5",
"babel-preset-env": "^1.7.0",
"babel-preset-es2015": "^6.24.1",
...
"jest": {
    "moduleFileExtensions": ["js"],
    "transform": { "^.+\\.js?$": "babel-jest" },
    "testRegex": "/tests/.*\\.(js)$"
  }

我有

.babelrc

{
  "presets": ["env"]
}

Answer 1

你在那里的几个地方绊倒了.主要:您不使用{}默认导入/导出.

这个:

export default { sayHello };

将对象导出为模块的默认导出.该对象具有单个属性sayHello,指的是该函数.要使该函数成为默认导出,请不要使用{}:

export default sayHello;

然后,在导入时,如果您想要默认导入,请不要使用{}:

import sayHello from '../../src/client/js/helloJest';

如果要导出命名导出,请使用{}:

export { sayHello };

和

import { sayHello } from '../../src/client/js/helloJest';

关于plunker的例子:https://embed.plnkr.co/f8PhOhULphQUrVXwdXF3/