I have a class which handles all the communication to any back-end RESTful service, it wraps up all the complexity of using HttpWebRequest and provides a simple API: 1: public interface IRestClient 2: { 3: Task<RestResponse<T>> GetAsync<T>(Uri url) where T : class ; 4: Task<RestResponse> PutAsync<T>(Uri url, T resource) where T : class ; 5: Task<RestResponse<T>> PostAsync<T>(Uri url, T resource) where T : class ; 6: Task<RestResponse> DeleteAsync(Uri url); 7: } The implementation of this class isn't relevant for this post - it's all about the behaviour. The behaviour is what I'm trying to test not the internal implementation... So how can I test this in a standard test fixture? I knew it was possible but I didn't think it would so easy... Having used asp.net WebAPI for hosting services in IIS I knew this was the tech stack I wanted to use, but could...