public void Cdr_ReturnsSecondValue_GivenAPair()
        {
            var expected = 4;
            var pair     = Problem5.Cons(3, expected);

            var actual = Problem5.Cdr(pair);

            Assert.AreEqual(expected, actual);
        }
        public void Car_ReturnsFirstValue_GivenAPair()
        {
            var expected = 3;
            var pair     = Problem5.Cons(expected, 4);

            var actual = Problem5.Car(pair);

            Assert.AreEqual(expected, actual);
        }
        public void Cons_ReturnsAPair_GivenTwoArguments()
        {
            var first  = 1;
            var second = 2;

            var pair = Problem5.Cons(first, second);

            Assert.AreEqual(first, pair.Item1);
            Assert.AreEqual(second, pair.Item2);
        }