public void OpEquals()
 {
     var momentum1 = new Momentum(300000, MomentumUnit.GramCentimetersPerSecond);
     var momentum2 = new Momentum(3, MomentumUnit.KilogramMetersPerSecond);
     var momentum3 = new Momentum(4, MomentumUnit.KilogramMetersPerSecond);
     (momentum1 == momentum2).ShouldBeTrue();
     (momentum2 == momentum1).ShouldBeTrue();
     (momentum1 == momentum3).ShouldBeFalse();
     (momentum3 == momentum1).ShouldBeFalse();
     momentum1.Equals(momentum2)
              .ShouldBeTrue();
     momentum1.Equals((object)momentum2)
              .ShouldBeTrue();
     momentum2.Equals(momentum1)
              .ShouldBeTrue();
     momentum2.Equals((object)momentum1)
              .ShouldBeTrue();
 }