@Test
public void testEquals() {

    assertThat(empty)
            .isEqualTo(new LinearId())
            .isNotEqualTo(single)
            .isNotEqualTo(dual);
    assertThat(single)
            .isEqualTo(new LinearId("single"))
            .isNotEqualTo(empty)
            .isNotEqualTo(dual);
    assertThat(dual)
            .isEqualTo(new LinearId("hello", "world"))
            .isNotEqualTo(empty)
            .isNotEqualTo(single);
}