Testing Delegating Handler

TestingDelegatingHandler.cs

/// <summary>
/// From: http://blogs.msmvps.com/theproblemsolver/2013/05/20/unit-testing-code-depending-on-the-asp-net-webapi-httpclient/
/// </summary>
/// <typeparam name="T"></typeparam>
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 => new HttpResponseMessage(statusCode) {
            Content = new StringContent(JsonConvert.SerializeObject(value), System.Text.Encoding.UTF8, "application/json")
        };
    }
    public TestingDelegatingHandler(Func<HttpRequestMessage, HttpResponseMessage> httpResponseMessageFunc) {
        _httpResponseMessageFunc = httpResponseMessageFunc;
    }

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