public void CompareToIsImplemented()
        {
            Permeance perm = Permeance.FromPerms(1);

            Assert.Equal(0, perm.CompareTo(perm));
            Assert.True(perm.CompareTo(Permeance.Zero) > 0);
            Assert.True(Permeance.Zero.CompareTo(perm) < 0);
        }
        public void CompareToThrowsOnNull()
        {
            Permeance perm = Permeance.FromPerms(1);

            Assert.Throws <ArgumentNullException>(() => perm.CompareTo(null));
        }
        public void CompareToThrowsOnTypeMismatch()
        {
            Permeance perm = Permeance.FromPerms(1);

            Assert.Throws <ArgumentException>(() => perm.CompareTo(new object()));
        }