Dependency Injection in tests about bulletproof-nodejs HOT 2 OPEN

Hi @Shisuki sorry for taking so long in responding.

This is a perfect example of the way of doing unit testing using dependency injections (asked here #65) thanks for taking the time to write a few snippets of code to showcase it.

For what I see the problem is with the Logger you are passing to the authentication service instance, did you instantiated it first? or are you just passing the class?

Since this the authentication service was written with the dependency injection pattern, you can pass a dummy object that respects the interface of Logger but without the implementation of the methods

 it('should return 201 if request is valid', async (done) => {
    const aMockedLoggerInstance = {
      info() {
           // nothing!
      }
   }

    const authenticationService = new AuthenticationService(
      User,
      aMockedLoggerInstance,
      mock<EventDispatcherInterface>(),
    );

    // You can also instantiate it by container, it returns the same error
    // const authenticationService = Container.get(AuthenticationService);

    const userDTO = factory.userDTO.build();
    const res = await request(server).post('/users').send(userDTO);

    expect(res.status).toBe(201);

    done();
  });

This can be pretty useful when you test services that depend on other and you don't want to execute the code but rather just make sure it is called.

from bulletproof-nodejs.

Hey @santiq thanks for your fast reply and I'm so sorry for taking so long to come back to you..

If you see in my example above it wasn't because I didn't use a dummy object for as a logger, that works fine, but when it works on the tests the implementation on the actual route breaks, and even in the test if I use the DI-container twice it also breaks (All shown above)

Anyway I've given up on using any DI-Container months ago as it ended up making my life more difficult and in the long term everything becomes tightly coupled with the Container.

Right now I've turned to pure DI with the use of index files as interfaces for the services and then barrel files to export exactly what I need, which gives me the best of both worlds and with just moderately more code configuration.

Thank you for your time!

from bulletproof-nodejs.