public void FibonacciUnder_Given10_ReturnArrayOfIntOfAllFibonacciNumbersUnder10()
        {
            var f = new EvenFibonacci();
            var expected = new int[5] {1, 2, 3, 5, 8};

            var actual = f.FibonacciUnder(10);

            CollectionAssert.AreEqual(expected, actual);
        }
        public void Filter_GivenArrayOf5FibsUnder10_ReturnOnlyEven()
        {
            var f = new EvenFibonacci();
            var expected = new int[2] {2, 8};
            var fibsUnder10 = new int[5] {1, 2, 3, 5, 8};

            var actual = f.Filter(fibsUnder10, x => x % 2 == 0);

            CollectionAssert.AreEqual(expected, actual);
        }