How can we mock `FirebaseAuth getInstance signInWithCustomTo

Question

How can we mock `FirebaseAuth getInstance signInWithCustomToken token addOnCompleteListener ` and other Task like `addOnSuccessListener` and `addOnFailureListener` using MockK

Samme Kleijn · Answer

I used to do a similar thing like this ``` MockK relaxed = true private lateinit var mockTask Task lt List lt FirebaseVisionBarcode gt gt ``` ```every mockTask addOnFailureListener any answers firstArg lt OnFailureListener gt onFailure mockk mockTask ``` To mock invoke a failure

Matej Drobnič · Answer

Don t mock tasks

Matej Drobnič · Answer

return real tasks for example `Tasks forException `

Kulwinder Singh · Answer

for `FirebaseAuth getInstance signInWithCustomToken token addOnCompleteListener` i have created ```lateinit var mockAuthTask Task lt AuthResult gt beforeEachTest every mockAuthTask addOnSuccessListener any answers firstArg lt OnCompleteListener lt AuthResult gt gt onComplete mockk ```

Kulwinder Singh · Answer

but its not working how can i do it < Samme Kleijn>

Kulwinder Singh · Answer

< Matej Drobnič> can you please give me more info

Matej Drobnič · Answer

instead of whole mock stuff just create dummy AuthResult and create real task ```val result = AuthResult val authTask = Tasks forResult result ```

Kulwinder Singh · Answer

< Matej Drobnič> but AuthResult is interface i don t know how to implement that class as Concrete

Kulwinder Singh · Answer

for this do i also have to update real code UseCases Repositories or just tests < Matej Drobnič> because i m not in situation to update real UseCases or repositories i am just fixing mocking issues

Kulwinder Singh · Answer

actually i have tried as < Samme Kleijn> suggested but i m getting this `Failure e=io mockk MockKException no answer found for Task 17 getException ` i think i m getting this because we are sending `AuthResult` as mockobject but now i don t know how to solve it disappointed

Matej Drobnič · Answer

just tests

Matej Drobnič · Answer

you can use `mockk ` instead of implementing AuthResult I guess

Matej Drobnič · Answer

or you can create your own `FakeAuthResult` class that implements the interface

Kulwinder Singh · Answer

< Matej Drobnič> actually `mock relaxed=true ` worked

Kulwinder Singh · Answer

but this is mocked but as you said don t mock tasks and return real what is Tasks forExceptions and how can i return real tasks is it going to connect to connect Firebase server and return real tasks < Matej Drobnič>

Matej Drobnič · Answer

Task is just a wraper that can return either result or exception

Matej Drobnič · Answer

it will not go to firebase

Matej Drobnič · Answer

`Tasks forResult mockk ` is a good compromise

Matej Drobnič · Answer

you don t mock the task but you mock real value

Matej Drobnič · Answer

but it would be even better if you don t mock anything and just return concrete AuthResult

Kulwinder Singh · Answer

Thanks < Matej Drobnič> amp < Samme Kleijn> both of yours solutions really helped me

Kulwinder Singh · Answer

after working everything currently i m getting ``` no answer found for SomeClass 3 setSomeVariable dummy ```

Kulwinder Singh · Answer

how can i add `every` for setters of fields

luke · Answer

Try here <https mockk io property backing fields>