CODEWITHSUNDEEP
dependency-injectionjestjsnestjs
Howard Scott
Howard Scott

Reputation: 331

NestJS dependency injection during unit test

I am stuck with the dependency injection problem of NestJS during the unit test with jest. Here is my codebase. app.controller.spec.ts

import { Test, TestingModule } from '@nestjs/testing';
import { AppController } from './app.controller';
import { AppService } from './app.service';

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

  beforeEach(async () => {
    const app: TestingModule = await Test.createTestingModule({
      controllers: [AppController],
      providers: [AppService],
    }).compile();

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

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

The problem is, there is dependency injection in app.service.ts

import { Injectable, CACHE_MANAGER, Inject } from "@nestjs/common";
import {Cache} from "cache-manager";

@Injectable()
export class AppService {
    constructor(@Inject(CACHE_MANAGER) private cacheManager: Cache) {}

    getHello(): string {
        return "Hello World!";
    }
}

In general, nest automatically performs dependency injection during bootup, but this isn't happening while running unit-test and giving me the following error:

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

Any idea how can I resolve this issue?

Upvotes: 2

Views: 4782

Answers (1)

Tim
Tim

Reputation: 502

You need to add the CACHE_MANAGER as a provider to your TestingModule:

const app: TestingModule = await Test.createTestingModule({
  controllers: [AppController],
  providers: [
    AppService,
    { provide: CACHE_MANAGER, useFactory: jest.fn() },
  ],
}).compile();

Upvotes: 11

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