Angular APP_INITIALIZER to load config file in tests

Question

I'm using this gist to read configuration file during application startup. This works fine but when doing unit tests I get error Cannot read property 'SomeProperty' of null.

I have added the provider to test as well

beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [ LoginComponent ],
      imports: [ReactiveFormsModule, RouterTestingModule, HttpModule],
      providers: [AuthService,
        SettingsService,
        AppConfig,
        {
            provide: APP_INITIALIZER,
            useFactory: initConfig,
            deps: [AppConfig],
            multi: true
        },
        ]
    })
    .compileComponents();
  }));

Any pointers to resolve this?. Thanks in advance.

Can you share more code? I don't see SomeProperty

yurzui
– yurzui

2017-05-08 08:47:41 +00:00
Commented May 8, 2017 at 8:47 — yurzui
– yurzui, Commented May 8, 2017 at 8:47
Have you figured out the solution?

pop
– pop

2017-09-11 14:41:34 +00:00
Commented Sep 11, 2017 at 14:41 — pop
– pop, Commented Sep 11, 2017 at 14:41

RocketMan · Accepted Answer · 2020-04-01 16:43:50Z

7

looks like there is an issue with how Angular treats the APP_INITIALIZER while running tests (see https://github.com/angular/angular/issues/24218).

The workaround for now is to call this before in each: test

  beforeEach(async () => {
    // until https://github.com/angular/angular/issues/24218 is fixed
    await TestBed.inject(ApplicationInitStatus).donePromise;
  });

for angular <9, use TestBed.get(...) instead.

answered Apr 1, 2020 at 16:43

RocketMan

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2 Comments

rolivencia Over a year ago

I tried it and it works great, but I wanted to know if this solution makes the test engine to wait until all APP_INITIALIZER promises are fulfilled. It should me marked as the correct answer, imho.

RocketMan Over a year ago

Hi Ramiro, yes I believe you are correct. My understanding is that this async/await pattern makes each test execution wait until the APP_INITIALIZER promise is fulfilled. Hope that helps!

jakefreeberg · Accepted Answer · 2017-09-13 20:40:34Z

1

I spun my wheels on something like this for a while. In the end I just provided a mock of the service in the "deps" of the APP_INITIALIZER provider and made sure it didn't do anything in the unit tests.

Then you just test the initializer and service independently and I think that's the best you can do.

answered Sep 13, 2017 at 20:40

jakefreeberg

215 bronze badges

Comments

Akostha · Accepted Answer · 2023-10-18 17:47:43Z

0

I think to separate test is a good idea. So, I mocked the config into my test and worked. Of course, I had to create another spec to ConfigService.

describe('My unit test', () => {
  
  const mock= { get myConfig() { return { url: 'http://mock' }; } };
  ...

  beforeEach(async () => {

    TestBed.configureTestingModule({
      imports: [...],
      declarations: [...],
      providers: [
        { provide: ConfigService, useValue: mock}
      ]
    }).compileComponents();
      ...
  });

...
});

edited Oct 18, 2023 at 17:47

answered May 21, 2020 at 13:51

Akostha

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1 Comment

Sudhir Kaushik Over a year ago

your reference link is dead

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