You can replace the core HttpMessageHandler with a fake one. Something that looks like this...
public class FakeResponseHandler : DelegatingHandler
{
private readonly Dictionary<Uri, HttpResponseMessage> _FakeResponses = new Dictionary<Uri, HttpResponseMessage>();
public void AddFakeResponse(Uri uri, HttpResponseMessage responseMessage)
{
_FakeResponses.Add(uri, responseMessage);
}
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
{
if (_FakeResponses.ContainsKey(request.RequestUri))
{
return Task.FromResult(_FakeResponses[request.RequestUri]);
}
else
{
return Task.FromResult(new HttpResponseMessage(HttpStatusCode.NotFound) { RequestMessage = request });
}
}
}
and then you can create a client that will use the fake handler.
var fakeResponseHandler = new FakeResponseHandler();
fakeResponseHandler.AddFakeResponse(new Uri("http://example.org/test"), new HttpResponseMessage(HttpStatusCode.OK));
var httpClient = new HttpClient(fakeResponseHandler);
var response1 = await httpClient.GetAsync("http://example.org/notthere");
var response2 = await httpClient.GetAsync("http://example.org/test");
Assert.Equal(response1.StatusCode,HttpStatusCode.NotFound);
Assert.Equal(response2.StatusCode, HttpStatusCode.OK);