@Test
public void testIndexes() {

    addChild("child1");
    addChild("child2");
    assertThat(engine.orderedView("ascending").stream().map(EntityHolder::getEntity)).containsExactly("child1", "child2");
    assertThat(engine.orderedView("descending").stream().map(EntityHolder::getEntity)).containsExactly("child2", "child1");
}