QUESTION: How to inject mock of firebase app in unit tests?

[soumak77]

I am using the following library to mock firebase in my unit tests: https://github.com/soumak77/firebase-mock

I am able to create an entire mock of the firebase SDK which I would like angularfire to use during unit testing. In order to achieve this, I would like to pass an instance of a mocked firebase.app.App to angularfire versus angularfire internally creating an app. How would I go about doing this?

[soumak77]

Anyone have feedback on this? Dependency injection is a must have to test apps that use this library.

[davideast]

@soumak77 There's nothing out-of-the-box for you to use, but it's possible to set it up yourself. Each AngularFire feature takes in some config tokens that are used to make an app. All you need to do is either alias the @firebase/app module to your firebase-mock module or use Webpack's NormalModuleReplacement plugin. That way it will switch out the real Firebase App module for the mock module and you won't have to do any code changes. Let me know if that sounds like that will work.

[soumak77]

@davideast angularfire2 already makes use of a FirebaseAppProvider. Is there a way to override this provider to allow me to control how the app is generated?

[davideast]

@soumak77 No, the FirebaseAppProvider is not used in the services. Due to Zone.js issues we have to create the app inside the service. Therefore your best bet it to replace the module at build time, this is also the easiest option.

[jamesdaniels]

Closing since we already have an issue to create testing docs, feel free to continue discussing.