public void AndGeneric_ReturnsConjunction()
        {
            var spec = new IntegerGreaterThanZero();
            var conjoinedSpec = spec.And<IntegerLessThanZero>();

            Assert.That(conjoinedSpec, Is.TypeOf<Conjunction<int>>());
            Assert.That(conjoinedSpec, Has.Property("Left").EqualTo(spec));
            Assert.That(conjoinedSpec, Has.Property("Right").TypeOf<IntegerLessThanZero>());
        }