OnCompleteListener never called while creating new Firebase user in espresso test case

Issue

For an integration test I want to do some tests with a very newly created user account. For that I create a Firebase user in my test case function like that:

    @Test
    fun registerAndSigningInWithVeryNewUser() {
        val auth = Firebase.auth
        auth.createUserWithEmailAndPassword(strEmail, strPassword)
            .addOnCompleteListener { task ->
                if (task.isSuccessful) {
                    // Sign in success, update UI with the signed-in user's information
                    Log.d(TAG, "createUserWithEmail:success")
                    // doing some test stuff
                } else {
                    // If sign in fails
                    Log.w(TAG, "createUserWithEmail:failure", task.exception)
                    assert(false)
                }
            }
    }

The new user account is created correctly. I can verify that in the Firebase Authentication dashboard. But the task in addOnCompleteListener is never called. I could not understand why.

Update: If I use the debugger and go step by step through the test function, the listener is called. So I think I need some idle code to wait for the async database call

Any hints?

Solution

The problem was, that the called function is an asynchronous call to a remote server (of cause).

The test case ends before the response could arrive. So I added an ugly Thread.sleep(10000).

    @Test
    fun registerAndSigningInWithVeryNewUser() {
        val auth = Firebase.auth
        auth.createUserWithEmailAndPassword(strEmail, strPassword)
            .addOnCompleteListener { task ->
                if (task.isSuccessful) {
                    // Sign in success, update UI with the signed-in user's information
                    Log.d(TAG, "createUserWithEmail:success")
                    // doing some test stuff
                } else {
                    // If sign in fails
                    Log.w(TAG, "createUserWithEmail:failure", task.exception)
                    assert(false)
                }
            }
            Thread.sleep(10000)
    }

But using Thread.sleep(...) is not always good: https://www.repeato.app/android-espresso-why-to-avoid-thread-sleep/ ore https://developer.android.com/training/testing/espresso/idling-resource

Answered By - Manuel Siebeneicher