public void MockAuthentication_ShouldUseMock() { string expected = "Hello from mock"; _client.Setup(c => c.Execute(It.IsAny <IRestRequest>())) .Returns(new RestResponse() { ResponseStatus = ResponseStatus.Completed, StatusCode = System.Net.HttpStatusCode.OK, Content = expected, }); var client = new SharpBucketV2(); client.MockAuthentication(_client.Object); var output = client.Get(null); output.ShouldBe(expected); }