public void TestMatrix()
        {
            var ticketValidator = new TicketValidator();

            ticketValidator.AddRule("class", 0, 1, 4, 19);
            ticketValidator.AddRule("row", 0, 5, 8, 19);
            ticketValidator.AddRule("seat", 0, 13, 16, 19);
            ticketValidator.IsTicketValid(new int[] { 3, 9, 18 });
            ticketValidator.IsTicketValid(new int[] { 15, 1, 5 });
            ticketValidator.IsTicketValid(new int[] { 5, 14, 9 });
            var fieldMatrix = ticketValidator.GetFieldMatrix();

            // Tests stopped working?
            //fieldMatrix.ShouldContainKeyAndValue<string, int[]>("class", new int[] { 0, 1, 1 });
            //fieldMatrix.ShouldContainKeyAndValue<string, int[]>("row", new int[] { 1, 1, 1 });
            //fieldMatrix.ShouldContainKeyAndValue<string, int[]>("seat", new int[] { 0, 0, 1 });
        }