Question

使用Jest和Enzyme，如何在setTimeout（）中运行代码？我也希望将延迟时间视为0，这样才不会延迟测试

正在测试的功能：

   functionToBeTested = () => {
           //more code...
            setTimeout(() => {
              console.log('not logging :/')
              return 'anything';
            }, 1000);
    }

测试：

it('functionToBeTested', () => { 
      expect(functionToBeTested).toEqual('anything');
})

Answer 1

这是单元测试解决方案：

index.ts：

export const functionToBeTested = () => {
  return new Promise(resolve => {
    setTimeout(() => {
      console.log('not logging :/');
      resolve('anything');
    }, 1000);
  });
};

index.spec.ts：

import { functionToBeTested } from './';

jest.useFakeTimers();

test('should return correctly', async () => {
  const logSpy = jest.spyOn(console, 'log');
  const promise = functionToBeTested();
  jest.runAllTimers();
  await expect(promise).resolves.toBe('anything');
  expect(logSpy).toBeCalledWith('not logging :/');
});

覆盖率100％的单元测试结果：

 PASS  src/stackoverflow/56942805/index.spec.ts (8.036s)
  ✓ should return correctly (10ms)

  console.log node_modules/jest-mock/build/index.js:860
    not logging :/

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |      100 |      100 |      100 |      100 |                   |
 index.ts |      100 |      100 |      100 |      100 |                   |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        9.608s

源代码：https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/56942805

如何使用Jest进入setTimeout函数

1 个答案: