How to pass in a mocked HttpClient in a .NET test?

Question

I have a service which uses Microsoft.Net.Http to retrieve some Json data. Great!

Of course, I don\'t want my unit test hitting the actual

Answer 1

I would just make a small change to @Darrel Miller's answer, which is using Task.FromResult to avoid the warning about an async method expecting an await operator.

public class FakeResponseHandler : DelegatingHandler
{
    private readonly Dictionary _FakeResponses = new Dictionary();

    public void AddFakeResponse(Uri uri, HttpResponseMessage responseMessage)
    {
        _FakeResponses.Add(uri, responseMessage);
    }

    protected override Task 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 });
        }
    }
}