@Test
void contains() {

    assertThat(Range.of(10L, 20L).contains(9)).isFalse();
    assertThat(Range.of(10L, 20L).contains(10)).isTrue();
    assertThat(Range.of(10L, 20L).contains(15)).isTrue();
    assertThat(Range.of(10L, 20L).contains(19)).isTrue();
    assertThat(Range.of(10L, 20L).contains(20)).isFalse();
}