@Test
public void resolvesAcuteAngle() {

    final double angle = new Acute<>().resolve(new MkProduct<Object>()).doubleValue();
    MatcherAssert.assertThat(angle, Matchers.greaterThanOrEqualTo(0.));
    MatcherAssert.assertThat(
        angle, Matchers.lessThanOrEqualTo(Math.PI / 2)
    );
}