@Test
public void testNotOf() {

    assertThat(PhenotypeTerm.notOf("id", "label"), equalTo(PhenotypeTerm.notOf("id", "label")));
    assertThat(PhenotypeTerm.notOf("id", "label"), not(equalTo(PhenotypeTerm.of("id", "label"))));
    assertThat(PhenotypeTerm.notOf("id", "label").isPresent(), is(false));
    assertThat(PhenotypeTerm.notOf("id", "label").notPresent(), is(true));
}