Fragment espresso with Dagger

FakeFragmentInjector.kt

inline fun <reified F : Fragment> createFakeFragmentInjector(crossinline block : F.() -> Unit)
    : DispatchingAndroidInjector<Any> {
  val myApp = InstrumentationRegistry.getInstrumentation().targetContext.applicationContext as MyApp
  val originalDispatchingActivityInjector = myApp.dispatchingActivityInjector
  var originalFragmentInjector: AndroidInjector<Any>? = null
  val fragmentInjector = AndroidInjector<Fragment> { fragment ->
    originalFragmentInjector?.inject(fragment)
    if (fragment is F) {
      fragment.block()
    }
  }
  val fragmentFactory = Factory<Fragment> { fragmentInjector }
  val fragmentMap = mapOf(Pair<Class <*>, Provider<Factory<*>>>(F::class.java, Provider { fragmentFactory }))
  val activityInjector = AndroidInjector<Activity> { activity ->
    originalDispatchingActivityInjector.inject(activity)
    if (activity is MainActivity) {
      originalFragmentInjector = activity.androidInjector()
      activity.fragmentInjector = DispatchingAndroidInjector_Factory.newInstance(fragmentMap, emptyMap())
    }
  }
  val activityFactory = Factory<Activity> { activityInjector }
  val activityMap = mapOf(Pair<Class <*>, Provider<Factory<*>>>(MainActivity::class.java, Provider { activityFactory }))
  return DispatchingAndroidInjector_Factory.newInstance(activityMap, emptyMap())
}