Owin hosted webapi 2.2. testing controller with mocked service.

I have webapi which for testing purposes I am hosting in owin. I have set it up using autofac. now when I am testing I want to inject moq dependencies. which I am not able to so far. I have read the documentation and did bit of research but I am missing something.

here is the testing code.

 [Test]
    public void Request_all_airports()
    {
        const int port = 8086;
        AirportCollection moqAirportCollection = new AirportCollection();
        moqAirportCollection.Airports = new List<Airport>{new Airport{IATA = "moq",Name = "moqName"}};

        using (WebApp.Start<Startup>("http://localhost:" + port))
        {
            using (var mock = AutoMock.GetLoose())
            {
                var moqObj =  mock.Mock<IAirportService>().Setup(x => x.GetAirports()).Returns(moqAirportCollection);

                var client = new HttpClient {BaseAddress = new Uri("http://localhost:" + port)};
                var response = client.GetAsync("/api/airport/get").Result;
                var body = response.Content.ReadAsStringAsync().Result;
                var airportCollection = JsonConvert.DeserializeObject<AirportCollection>(body);
            }
        }
    }

Please have a look. let me know what I am missing. if you want to look at controller code or any other piece do let me know .

Thanks