Utility class for test enabling the System.Net.Http.HttpClient

gistfile1.txt

    public class TestingDelegatingHandler<T> : DelegatingHandler
    {
        private Func<HttpRequestMessage, HttpResponseMessage> _httpResponseMessageFunc;

        public TestingDelegatingHandler(T value)
            : this(HttpStatusCode.OK, value)
        { }

        public TestingDelegatingHandler(HttpStatusCode statusCode)
            : this(statusCode, default(T))
        { }

        public TestingDelegatingHandler(HttpStatusCode statusCode, T value)
        {
            _httpResponseMessageFunc = request => request.CreateResponse(statusCode, value);
        }

        public TestingDelegatingHandler(
            Func<HttpRequestMessage, HttpResponseMessage> httpResponseMessageFunc)
        {
            _httpResponseMessageFunc = httpResponseMessageFunc;
        }

        protected override Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request, CancellationToken cancellationToken)
        {
            return Task.Factory.StartNew(() => _httpResponseMessageFunc(request));
        }
    }

        [TestMethod]
        public void WhenGettingAllBooksTheyShouldBeReturned()
        {
            // Arrange
            var books = new[]
            {
                new Book{Id = 1, Author = "Me", Title = "Book 1"},
                new Book{Id = 2, Author = "You", Title = "Book 2"}
            };
            var testingHandler = new TestingDelegatingHandler<Book[]>(books);
            var server = new HttpServer(new HttpConfiguration(), testingHandler);
            var client = new BooksClient(new HttpClient(server));

            // Act
            var booksReturned = client.GetBooks();

            // Assert
            Assert.AreEqual(2, booksReturned.Count());
        }