DEPRECATED

EspressoTextInputLayoutUtils.java

class EspressoTextInputLayoutUtils{
  /*
   * Use this method to find the EditText within the TextInputLayout. Useful for typing into the TextInputLayout
   */
  public static ViewInteraction onEditTextWithinTilWithId(@IdRes int textInputLayoutId) {
    //Note, if you have specified an ID for the EditText that you place inside
    //the TextInputLayout, use that instead - i.e, onView(withId(R.id.my_edit_text));
    return onView(allOf(isDescendantOfA(withId(textInputLayoutId)), isAssignableFrom(EditText.class)));
  }
  
  /*
   * Use this method to find the error view within the TextInputLayout. Useful for asseting that certain errors are displayed to the user
   */
  public static ViewInteraction onErrorViewWithinTilWithId(@IdRes int textInputLayoutId) {
    return onView(allOf(isDescendantOfA(withId(textInputLayoutId)), not(isAssignableFrom(EditText.class)), isAssignableFrom(TextView.class)));
  }
  
  //Example usage
  @Test
  public void testUsernameTooShortShowsError(){
    onEditTextWithinTilWithId(R.id.tilUsername).perform(typeText("user123"), closeSoftKeyboard()); 
    onView(withId(R.id.sign_up)).perform(click());//Assume there is a button that you click
    onErrorViewWithinTilWithId(R.id.tilUsername).check(matches(withText("Username too short")));
  }
}

onErrorViewWithinTilWithId doesn't workr for me

@stMayhem what problem do you see? Is the error view not found at all?
I have not updated this gist in 2 years and it is possible that the implementation of TextInputLayout has changed recently thus causing this code to break (you might have noted that it depends on implementation details of TIL).

here also does not work, it asks to create the class matches