@Test
public void testReturnChildOfParents() throws Exception {

    assertEquals(mViewParent1Child1, mSubject.findViewByIdEfficient(ID_PARENT_1, ID_CHILD_1));
    assertEquals(mViewParent1Child2, mSubject.findViewByIdEfficient(ID_PARENT_1, ID_CHILD_2));
    assertEquals(mViewParent2Child1, mSubject.findViewByIdEfficient(ID_PARENT_2, ID_CHILD_1));
    assertEquals(mViewParent2Child2, mSubject.findViewByIdEfficient(ID_PARENT_2, ID_CHILD_2));
}