public RoomsController(AbstractExpediaService expediaService)
        {
            if (expediaService == null) // Guard Clause
            {
                throw new ArgumentNullException("expediaService");
            }

            _expediaService = expediaService;
        }
        public DistanceController(IDistanceMatrixService distanceMatrixService, AbstractExpediaService expediaService)
        {
            if (distanceMatrixService == null)
            {
                throw new ArgumentNullException("distanceMatrixService");
            }

            if (expediaService == null)
            {
                throw new ArgumentNullException("expediaService");
            }

            _expediaService = expediaService;
            _distanceMatrixService = distanceMatrixService;
        }
        public SearchController(AbstractExpediaService expediaService, IGeoLookupService lookupService)
        {
            if (expediaService == null) // Guard clause
            {
                throw new ArgumentNullException("expediaService");
            }

            if (lookupService == null) // Guard clause
            {
                throw new ArgumentNullException("lookupService");
            }

            _expediaService = expediaService;
            _lookUpService = lookupService;
        }
        public HotelsController(AbstractExpediaService expediaService, IGeoLookupService geoLookupService)
        {
            if (expediaService == null) // Guard Clause
            {
                throw new ArgumentNullException("expediaService");
            }

            if (geoLookupService == null) // Guard Clause
            {
                throw new ArgumentNullException("geoLookupService");
            }

            _lookUpService = geoLookupService;
            _expediaService = expediaService;
        }