public static void Test_Envelope_WithLongitude(double value)
        {
            //arrange
            RequestEnvelope envelope = new RequestEnvelope();

            //act
            envelope.WithLongitude(value);

            //assert
            Assert.AreEqual(value, envelope.Longitude);
        }
        public static void Test_Envelope_Extensions_Throw_On_Null_Envelope()
        {
            //arrange
            RequestEnvelope envelope = null;

            //assert
            Assert.Throws <ArgumentNullException>(() => envelope.WithAltitude(5));
            Assert.Throws <ArgumentNullException>(() => envelope.WithLatitude(5));
            Assert.Throws <ArgumentNullException>(() => envelope.WithLongitude(5));
            Assert.Throws <ArgumentNullException>(() => envelope.WithAuthTicket(new AuthTicket()));
            Assert.Throws <ArgumentNullException>(() => envelope.WithMessage(new Request()));
            Assert.Throws <ArgumentNullException>(() => envelope.WithRequestID());
            Assert.Throws <ArgumentNullException>(() => envelope.WithAuthenticationMessage(AuthType.Google, ""));
        }