Unable to run tests when connected to two or more Firebase apps

[michaelyfan]

Version info

Angular: 9.0.2

Firebase: 7.8.0

AngularFire: ^6.0.0-rc.1

Other (e.g. Ionic/Cordova, Node, browser, operating system):

• node: 14.4.0
• npm 6.14.4
• macOS 10.15.5

How to reproduce these conditions

Stackblitz example:
https://stackblitz.com/edit/angular-fire-start-nv2mnn

Steps to set up and reproduce

The Stackblitz example has a crude reproduction of my code.

Yes, I'm aware I intentionally left out .initializeApp() in my code. More on that below...

Sample data and security rules

Firebase project with no security rules--this isn't really relevant to my issue

Debug output

When running npm run test, I receive this error in my Karma HTML runner:

NullInjectorError: R3InjectorError(DynamicTestModule)[FirebaseHelperService -> RoutesAngularFirestore -> InjectionToken angularfire2.app.options -> InjectionToken angularfire2.app.options]: 
  NullInjectorError: No provider for InjectionToken angularfire2.app.options!

Screenshot:

There are many Google-able resolutions to this problem, all which involve invoking .initializeApp(). I'm aware I intentionally left that out. More on that below...

Expected behavior

My tests run as normal!

Actual behavior

See "Debug output"

Special notes

I'm trying to connect my app to two Firebase projects at once. I've scoured around and there aren't really any official/standardized procedures for this, so I'm using this solution suggested in a comment on an open repo. I tried to recreate it as best as I could in the stackblitz.

The solution works well, but it doesn't require that I invoke initializeApp anywhere. So that thing where you go

imports: [
    AngularFireModule.initializeApp(yourFirebaseConfig),
    AngularFirestoreModule,
    // ... the rest
],

is not something that I have in my project.
I've always been a bit uncomfortable with this, since it doesn't seem like common practice at all, but I don't know how get over it, since doing the above would force me to choose a single Firebase project, which is what I'm trying to avoid all this time. I'm also worried that initializing w.r.t a single Firebase project, and then having providers for two Firebase projects, would cause some sort of unexpected behavior / conflict / headache which is why I haven't bothered.

So, how do I get past this? I'd like to connect to two Firebase projects, but I'd also like my tests to run, and know once and for all if what I'm doing is "the way" or not.

[jamesdaniels]

AngularFireModule expects the options available to DI via the FIREBASE_OPTIONS, which is provided automatically when you call the initializeApp static method. I've been meaning to document how to work with multiple apps better.

[BaoLopTruong]

Hey guy, I have problem too. Can u help me how to fix ? tks