@Test
public void toStringPrintsAngle() {

    final Acute<Object> acute = new Acute<>();
    final Double angle = acute.resolve(new MkProduct<Object>()).doubleValue();
    final int precision = 6;
    MatcherAssert.assertThat(
        acute.toString(),
        Matchers.containsString(
            Double.toString(angle * 2 / Math.PI).substring(0, precision)
        )
    );
}