@Test
public void testEquals() {

    assertThat(EMPTY).isEqualTo(CubeId.root());
    assertThat(EMPTY).isNotEqualTo(null);
    assertThat(EMPTY).isNotEqualTo(SECTOR_REGION);
    assertThat(SECTOR_REGION).isEqualTo(CubeId.root("sector", "region"));
    assertThat(SECTOR_REGION).isNotEqualTo(INDUSTRY);
}