Example for mocking RestSharps IRestClient ExecuteAsync method using Moq

RestSharpExecuteAsyncMoq.cs

using Moq;
using NUnit.Framework;
using RestSharp;
using System;
using System.Net;

namespace RestsharpTests
{
    [TestFixture]
    public class RestsharpExecuteAsyncMoq
    {
        [Test]
        public void ExecuteAsyncWithMoq()
        {
            var restClient = new Mock<IRestClient>();

            restClient
                .Setup(x => x.ExecuteAsync(
                    It.IsAny<IRestRequest>(),
                    It.IsAny<Action<IRestResponse, RestRequestAsyncHandle>>()))
                .Callback<IRestRequest, Action<IRestResponse, RestRequestAsyncHandle>>((request, callback) =>
                {
                    callback(new RestResponse { StatusCode = HttpStatusCode.OK }, null);
                });

            restClient.Object.ExecuteAsync(new RestRequest(), (response, handle) =>
            {
                Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);
            });
        }
    }
}