public async Task Order_Null_BadRequestResult()
        {
            // arrange
            var controller = new NumberOrderingController();

            // act
            IActionResult result = await controller.Order(null);

            var badResult = result as BadRequestResult;

            // assert
            Assert.IsNotNull(badResult);
            Assert.AreEqual(400, badResult.StatusCode);
        }
        public async Task Order_NotDistinct_BadRequestResult()
        {
            // arrange
            var stubNumbers = new int[] { 5, 2, 2, 8, 10, 10, 1 };
            var controller  = new NumberOrderingController();

            // act
            IActionResult result = await controller.Order(stubNumbers);

            var badResult = result as BadRequestResult;

            // assert
            Assert.IsNotNull(badResult);
            Assert.AreEqual(400, badResult.StatusCode);
        }
        public async Task Order_ValidNumbers_OkObjectResult()
        {
            // arrange
            var stubNumbers = new int[] { 5, 2, 8, 10, 1 };
            var controller  = new NumberOrderingController();

            // act
            IActionResult result = await controller.Order(stubNumbers);

            var okResult = result as OkObjectResult;

            // assert
            Assert.IsNotNull(okResult);
            Assert.AreEqual(200, okResult.StatusCode);
        }