example.kt

interface InteractionAnswerRetriever {
  fun getPendingAnswer(): InteractionObject
}

class TextInputInteractionView: TextView, InteractionAnswerRetriever {
  override fun getPendingAnswer(): InteractionObject {
    return InteractionObject.newBuilder().setNormalizedAnswer(text).build()
  }
}

... testing the view ...

@Test
fun testInputInteractionView_withInputtedText_hasCorrectPendingAnswer() {
  onView(withId(R.id.test_text_input_interaction_view)).perform(text("Test value"))
  
  activityScenario.onActivity { activity ->
    val textAnswerRetriever = activity.findViewById(R.id.test_text_input_interaction_view) as InteractionAnswerRetriever
    assertThat(textAnswerRetriever.objectTypeCase).isEqualTo(InteractionObject.ObjectTypeCase.NORMALIZED_STRING)
    assertThat(textAnswerRetriever.normalizedString).isEqualTo("Test value")
  }
}