fake() for all the unit tests

Fake.kt

val ALL_FAKES = listOf(
    FakePostLoginUseCase::class,
    // all fake classes go here
)

/**
 * Finds and initializes an instance of
 * class [T] if it exists in [ALL_FAKES].
 *
 * If it doesn't, a [FakeNotFoundException] is thrown
 */
inline fun <reified T : Any> fake(): T {
    val match = ALL_FAKES.firstOrNull {
        it.isSubclassOf(T::class)
    }

    match ?: throw fakeNotFoundException<T>()

    return match.createInstance() as T
}

inline fun <reified T : Any> fakeNotFoundException() = FakeNotFoundException(T::class.simpleName)

class FakeNotFoundException(kClass: String?) : Throwable("No matching fakes were found for type: $kClass")