Question

我在一个文件中有两个功能

// file1.ts
const function1 = () => {
  return 123;
};
const function2 = () => {
  return function1() + 2;
}

export{
  function1,
  function2
}

我正在使用功能2的玩笑编写单元测试，但是我无法模拟function1

我只是尝试使用jest.spyOn来模拟function1

import * as helperFunctions from "file1";
describe("test function2 ", () => {
    let functionSpy: any;
    beforeAll(() => {
        functionSpy = jest.spyOn(helperFunctions , "function1 ");
    });

    afterAll(() => {
        functionSpy.mockReset();
    });
    test("test", () => {
        functionSpy.mockReturnValue(1);
        expect(helperFunctions.function2()).toEqual(3);
    });
});

在我的测试中，function1没有被模拟，它仍然调用实际的实现。任何帮助表示赞赏。

Answer 1

这是解决方案：

index.ts：

const function1 = () => {
  return 123;
};
const function2 = () => {
  return exports.function1() + 2;
};

exports.function1 = function1;
exports.function2 = function2;

单元测试：

describe('test function2 ', () => {
  const helperFunctions = require('./');
  helperFunctions.function1 = jest.fn();
  test('test', () => {
    helperFunctions.function1.mockReturnValueOnce(1);
    expect(helperFunctions.function2()).toEqual(3);
  });
});

单元测试结果：

 PASS  src/stackoverflow/56354252/index.spec.ts
  test function2 
    ✓ test (8ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        2.696s, estimated 3s

您可以找到此问题的更多详细信息：https://github.com/facebook/jest/issues/936#issuecomment-214939935

模拟模块中的特定功能

1 个答案: