public async Task PlayAsync() { const string rawXmlContent = "<itemName>MyItem</itemName>"; var httpMock = new MockHttpMessageHandler(); httpMock.Expect(HttpMethod.Post, "http://1.2.3.4:8090/select") .WithPartialContent(rawXmlContent) .Respond(HttpStatusCode.Created); var deviceMock = new Mock <ISpeaker>(); deviceMock.Setup(x => x.IpAddress).Returns("1.2.3.4"); var httpClient = new HttpClient(httpMock); var testee = new BoseConnection(httpClient); await testee.PlayAsync(deviceMock.Object, new ContentItem { ItemName = "MyItem" }); httpMock.VerifyNoOutstandingExpectation(); }