public static void ThrowsArgumentNull()
        {
            Action nullLuisClient = () => new LuisNLUTestClient(null);

            nullLuisClient.Should().Throw <ArgumentNullException>().And.ParamName.Should().Be("luisClient");

            using (var luis = new LuisNLUTestClientBuilder().Build())
            {
                Func <Task> nullTestUtterance       = () => luis.TestAsync(default(JToken));
                Func <Task> nullTestSpeechUtterance = () => luis.TestSpeechAsync(null);
                nullTestUtterance.Should().Throw <ArgumentNullException>().And.ParamName.Should().Be("query");
                nullTestSpeechUtterance.Should().Throw <ArgumentException>().And.ParamName.Should().Be("speechFile");
            }
        }