如何开玩笑地模拟和避免 express-validator 调用？

Question

我们的代码库中有如下代码：

@Validate(Param1)
async post(request, responseHandler) {
 // some code
}

我正在尝试测试 post 函数。但要避免评估 @Validate 函数。 Validate 是另一个模块中的函数。

// validator.ts
export const Validate = () => {
  // some code
}

怎么办？ .

Answer 1

您可以使用 jest.mock(moduleName, factory, options) 创建模拟的 Validate 装饰器，而不是使用可能有很多验证规则的真实 Validate 装饰器。

例如

index.ts:

import { Validate } from './validator';

export class Controller {
  @Validate('params')
  async post(request, responseHandler) {
    console.log('real post implementation');
  }
}

validator.ts:

export const Validate = (params) => {
  return (target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<any>) => {
    const oFunc = descriptor.value;
    descriptor.value = function inner(...args: any[]) {
      console.log('real validator decorator implementation');
      // lots of validation
      const rval = oFunc.apply(this, args);
      return rval;
    };
  };
};

index.test.ts:

import { Validate } from './validator';
import { mocked } from 'ts-jest/utils';

jest.mock('./validator');

describe('63531414', () => {
  afterAll(() => {
    jest.resetAllMocks();
  });
  it('should pass', async () => {
    mocked(Validate).mockImplementationOnce((params) => {
      return (target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<any>) => {
        const oFunc = descriptor.value;
        descriptor.value = function inner(...args: any[]) {
          console.log('mocked validator decorator implementation');
          const rval = oFunc.apply(this, args);
          return rval;
        };
      };
    });
    const { Controller } = require('./');
    const logSpy = jest.spyOn(console, 'log');
    const ctrl = new Controller();
    await ctrl.post({}, () => {});
    expect(Validate).toBeCalledWith('params');
    expect(logSpy).toBeCalledWith('real post implementation');
  });
});

带有覆盖率报告的单元测试结果：

 PASS  src/Whosebug/63531414/index.test.ts (12.634s)
  63531414
    ✓ should pass (154ms)

  console.log node_modules/jest-mock/build/index.js:860
    mocked validator decorator implementation

  console.log node_modules/jest-mock/build/index.js:860
    real post implementation

--------------|----------|----------|----------|----------|-------------------|
File          |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
--------------|----------|----------|----------|----------|-------------------|
All files     |    45.45 |      100 |       25 |    45.45 |                   |
 index.ts     |      100 |      100 |      100 |      100 |                   |
 validator.ts |    14.29 |      100 |        0 |    14.29 |       2,3,4,5,7,8 |
--------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        14.354s

源代码：https://github.com/mrdulin/jest-codelab/tree/master/src/Whosebug/63531414

如何开玩笑地模拟和避免 express-validator 调用？

How to mock and avoid express-validator calls in jest?

node.js

mocking

jestjs

express-validator

ts-jest