How to use injected depencies inside an instrumentation test

Question

I set up my instrumentation tests to use the appropriate test app dependencies using dagger.

My TestApplicationComponent

@Component(modules = [
    (AndroidInjectionModule::class),
    (TestApplicationModule::class),
    (ActivityBuilderTest::class),
    (FragmentBuilderTest::class),
    (AndroidSupportInjectionModule::class)])
@Singleton
interface TestApplicationComponent: AndroidInjector<TestApplication> {

    @Component.Factory
    abstract class Builder: AndroidInjector.Factory<TestApplication>
}

My TestApplication class

class TestApplication : DaggerApplication() {

    override fun applicationInjector(): AndroidInjector<out DaggerApplication> {
        return DaggerTestApplicationComponent.factory().create(this)
    }
}

In my test instrumentation setup (@Before), I need to call a RepositoryImplementation, also used in the app, to save an object to the database for some specific test cases. For example, save an "ongoing status", to make sure when a user opens the app it redirects to the correct screen.

The objective would be for something like this to work:

Test Class:

class ActivityTest {

   @Inject
   lateinit var appointmentRepository: AppointmentRepository

   @Before
   fun setUp() {
      appointmentRepository.saveAppointmentStatus()
   }

   **TESTING**
}

How can I achieve this? Currently and obviously appointmentRepository remains null.