public void setBottomPadding(int bottomPadding) {
    mBottomPadding = bottomPadding;
    for (int childIndex = 0; childIndex < getChildCount(); childIndex++) {
      if (getChildAt(childIndex) instanceof MainChild v) {
        v.setBottomOffset(bottomPadding);
      }
    }
  }
@Test
  public void testSettingPadding() {
    AnyKeyboardView mock = Mockito.mock(AnyKeyboardView.class);
    mUnderTest.addView(mock);
    Mockito.verify(mock).setBottomOffset(0);

    View mockRegular = Mockito.mock(View.class);
    mUnderTest.addView(mockRegular);

    mUnderTest.setBottomPadding(10);
    Mockito.verify(mock).setBottomOffset(10);

    AnyKeyboardView mock2 = Mockito.mock(AnyKeyboardView.class);
    mUnderTest.addView(mock2);
    Mockito.verify(mock2).setBottomOffset(10);
  }