@Test
public void span() {

	assertThat(Range.exactly(5).span(Range.exactly(6)))
			.isEqualTo(Range.of(5, 6))
			.isEqualTo(Range.exactly(6).span(Range.exactly(5)));
	assertThat(Range.of(5, 7).span(Range.exactly(6)))
			.isEqualTo(Range.of(5, 7));
}