NestedLayoutActivityTest.java

public class NestedLayoutActivityTest {

  @Rule
  public ActivityTestRule mActivityRule = new ActivityTestRule(NestedLayoutActivity.class);

  @Test
  public void performClickOnTextView() {
    onView(withId(R.id.parent_container)).perform(new ViewAction() {

      @Override
      public Matcher<View> getConstraints() {
        return isDisplayed();
      }

      @Override
      public String getDescription() {
        return "Performing click";
      }

      @Override
      public void perform(UiController uiController, View view) {
        //The view which we got in argument is the same view which Espresso found using onView(withId(R.id.parent_container))
        LinearLayout parentLinearLayout = (LinearLayout) view;
        //Get the LinearLayout inside the LinearLayout
        LinearLayout linearLayout = (LinearLayout) parentLinearLayout.getChildAt(0);
        //Get the Button inside the inner LinearLayout
        TextView helloWordTextView = (TextView) linearLayout.getChildAt(0);
        helloWordTextView.performClick();
      }
    });
  }
}