Mock service for unit tests

[ghost]

Hi, Great package.

I am having some trouble mocking the service for my unit tests. It seems like, if I provide the SendGridModule in the imports it ignores the provider override and actually sends the email. If I do not provide the SendGridModule this is the error

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

const mockSendGridService = {
  send: jest.fn().mockResolvedValue(null)
};

const mockConfigService = {
  get: jest.fn().mockReturnValue('')
};

describe('MailerService', () => {
  let service: MailerService;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [
        MailerService,
        { provide: SendGridService, useValue: mockSendGridService },
        { provide: ConfigService, useValue: mockConfigService }
      ]
    }).compile();

    service = module.get<MailerService>(MailerService);
  });

  it('should be defined', () => {
    expect(service).toBeDefined();
  });
});

can you tell me where im going wrong?

Thanks

[jquinteros-applaudo]

Hey, you need to pass SENDGRID_TOKEN const from nestjs-sendgrid package in the provide property when creating your testing module. And just in case, pass the same value when getting the provider inside the beforeEach function

tl;dr -> The DI identifier/token for the SendGrid service is not the class, it's the constant SENDGRID_TOKEN