Question

我正在尝试为嵌套函数编写单元测试，如下所示：

myFunction.js

const anotherFunction = require('./anotherFunction.js')

module.exports = (app, io) => {
  return (req, res) => {
    const { id, value } = req.query
    req.app.locals['target' + id].pwmWrite(value)
    anotherFunction(app, io)
    res.send({ value })
  }
}

我想测试是否pwmWrite()和anotherFunction()被调用。

但是由于return (req, res) => {}和导入的函数，我遇到了一些问题。

这是我的尝试，不起作用：

myFunction.test.js

test('should call pwmWrite() and anotherFunction()', async () => {
  const app = {}
  const io = { emit: jest.fn() }
  const req = {
    app: {
      locals: {
        target1: { pwmWrite: () => 25 }
        }
      }
    }
  }
  expect.assertions(1)
  expect(req.app.locals.target1.pwmWrite).toHaveBeenCalled()
  await expect(myFunction(app, io)).resolves.toEqual(25)
})

Answer 1

这是解决方案：

myFunction.js：

const anotherFunction = require('./anotherFunction.js');

module.exports = (app, io) => {
  return (req, res) => {
    const { id, value } = req.query;
    req.app.locals['target' + id].pwmWrite(value);
    anotherFunction(app, io);
    res.send({ value });
  };
};

anotherFunction.js：

module.exports = (app, io) => {
  return 'do something';
};

单元测试：

jest.mock('./anotherFunction');

const myFunction = require('./myFunction');
const anotherFunction = require('./anotherFunction');

describe('test suites', () => {
  test('should call pwmWrite() and anotherFunction()', () => {
    const app = {};
    const io = { emit: jest.fn() };
    const id = '1';
    const value = 'jest';
    const req = {
      query: { id, value },
      app: {
        locals: {
          target1: { pwmWrite: jest.fn() }
        }
      }
    };
    const res = { send: jest.fn() };
    myFunction(app, io)(req, res);
    expect(anotherFunction).toBeCalledWith(app, io);
    expect(req.app.locals.target1.pwmWrite).toBeCalledWith(value);
  });
});

带有覆盖率报告的单元测试结果：

 PASS  src/stackoverflow/52845000/myFunction.spec.js
  test suites
    ✓ should call pwmWrite() and anotherFunction() (5ms)

--------------------|----------|----------|----------|----------|-------------------|
File                |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
--------------------|----------|----------|----------|----------|-------------------|
All files           |    88.89 |      100 |    66.67 |    88.89 |                   |
 anotherFunction.js |       50 |      100 |        0 |       50 |                 2 |
 myFunction.js      |      100 |      100 |      100 |      100 |                   |
--------------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        3.113s

以下是完整的演示：https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/52845000

JestJS：如何测试嵌套（异步）函数中的调用函数

1 个答案: