public void FibonacciSequence_DoesNotOverflowAtElement46()
        {
            var seq     = new FibonacciSequence();
            var value46 = seq.ElementAt(45);
            var value47 = seq.ElementAt(46);

            Assert.Greater(value47, value46);
        }
        public void FibonacciSequence_Element_IsValue(int n, int expected)
        {
            var seq    = new FibonacciSequence();
            var result = seq.ElementAt(n);

            Assert.AreEqual(expected, result);
        }