Nestjs单元测试模拟方法保护

问题描述

我已经开始与NestJS合作，有一个关于嘲弄警卫的问题用于单元测试。我正在尝试测试附加了Method Guard的基本HTTPcontroller。

我的问题开始于我向警卫注入服务时(我需要警卫的ConfigService)。

运行测试时，DI无法解析防护

  ● AppController › root › should return "Hello World!"

    Nest can't resolve dependencies of the ForceFailGuard (?). Please make sure that the argument at index [0] is available in the _RootTestModule context.

我的强制故障保护：

import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common';
import { ConfigService } from './config.service';

@Injectable()
export class ForceFailGuard implements CanActivate {

  constructor(
    private configService: ConfigService,
  ) {}

  canActivate(context: ExecutionContext) {
    return !this.configService.get().shouldFail;
  }
}

规格文件：

import { CanActivate } from '@nestjs/common';
import { Test, TestingModule } from '@nestjs/testing';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { ForceFailGuard } from './force-fail.guard';

describe('AppController', () => {
  let appController: AppController;

  beforeEach(async () => {

    const mock_ForceFailGuard = { CanActivate: jest.fn(() => true) };

    const app: TestingModule = await Test
      .createTestingModule({
        controllers: [AppController],
        providers: [
          AppService,
          ForceFailGuard,
        ],
      })
      .overrideProvider(ForceFailGuard).useValue(mock_ForceFailGuard)
      .overrideGuard(ForceFailGuard).useValue(mock_ForceFailGuard)
      .compile();

    appController = app.get<AppController>(AppController);
  });

  describe('root', () => {

    it('should return "Hello World!"', () => {
      expect(appController.getHello()).toBe('Hello World!');
    });

  });
});

我找不到有关此问题的示例或文档。我是遗漏了什么，还是这是一个真正的问题？

感谢您的帮助，谢谢。

推荐答案

提供的示例repo有3个问题：

1. Nestjs v6.1.1中存在错误，.overrideGuard()-请参阅https://github.com/nestjs/nest/issues/2070

   我已确认在6.5.0中已修复。

2. ForceFailGuard在providers中，但其依赖项(ConfigService)在已创建的TestingModule中不可用。

   如果要模拟ForceFailGuard，只需将其从providers中删除，让.overrideGuard()执行其工作即可。

3. mock_ForceFailGuard将CanActivate作为属性，而不是canActivate。

工作示例(nestjs v6.5.0)：

import { CanActivate } from '@nestjs/common';
import { Test, TestingModule } from '@nestjs/testing';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { ForceFailGuard } from './force-fail.guard';

describe('AppController', () => {
  let appController: AppController;

  beforeEach(async () => {
    const mock_ForceFailGuard: CanActivate = { canActivate: jest.fn(() => true) };

    const app: TestingModule = await Test
      .createTestingModule({
        controllers: [AppController],
        providers: [
          AppService,
        ],
      })
      .overrideGuard(ForceFailGuard).useValue(mock_ForceFailGuard)
      .compile();

    appController = app.get<AppController>(AppController);
  });

  describe('root', () => {
    it('should return "Hello World!"', () => {
      expect(appController.getHello()).toBe('Hello World!');
    });
  });
});

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