public void TestGetTicketsCountForDeletedTicketsReturnsZero()
        {
            ITicketCatalog catalog = new TicketCatalog();
            catalog.AddAirTicket(from: "Sofia", to: "Varna", dateTime: new DateTime(2015, 1, 29, 7, 40, 00), price: 211.00M, airline: "New Air", flightNumber: "SV1234");
            catalog.AddTrainTicket("Sofia", "Varna", new DateTime(2015, 1, 28, 7, 45, 00), 26.00M, 16.30M);
            catalog.AddBusTicket("Sofia", "Varna", dateTime: new DateTime(2015, 1, 29, 7, 40, 00), price: 25.00M, travelCompany: "Biomet");
            Assert.AreEqual(1, catalog.GetTicketsCount(TicketType.Air));
            Assert.AreEqual(1, catalog.GetTicketsCount(TicketType.Train));
            Assert.AreEqual(1, catalog.GetTicketsCount(TicketType.Bus));

            catalog.DeleteAirTicket("SV1234");
            catalog.DeleteTrainTicket("Sofia", "Varna", new DateTime(2015, 1, 28, 7, 45, 00));
            catalog.DeleteBusTicket("Sofia", "Varna", dateTime: new DateTime(2015, 1, 29, 7, 40, 00), travelCompany: "Biomet");
            Assert.AreEqual(0, catalog.GetTicketsCount(TicketType.Air));
            Assert.AreEqual(0, catalog.GetTicketsCount(TicketType.Train));
            Assert.AreEqual(0, catalog.GetTicketsCount(TicketType.Bus));
        }
        public void TestFindTicketsCheckDeletedTickets()
        {
            ITicketCatalog catalog = new TicketCatalog();
            catalog.AddAirTicket(from: "Sofia", to: "Varna", dateTime: new DateTime(2015, 1, 29, 7, 40, 00), price: 211.00M, airline: "New Air", flightNumber: "SV1234");
            catalog.AddTrainTicket("Sofia", "Varna", new DateTime(2015, 1, 28, 7, 45, 00), 26.00M, 16.30M);
            catalog.AddBusTicket("Sofia", "Varna", dateTime: new DateTime(2015, 1, 29, 7, 40, 00), price: 25.00M, travelCompany: "Biomet");
            var cmdResult = catalog.FindTicketsInInterval(new DateTime(1980, 1, 1, 0, 0, 0), new DateTime(2050, 2, 1, 0, 0, 0));
            var expectedCmdResult = "[28.01.2015 07:45; train; 26.00] " + "[29.01.2015 07:40; air; 211.00] " + "[29.01.2015 07:40; bus; 25.00]";
            Assert.AreEqual(expectedCmdResult, cmdResult);

            catalog.DeleteAirTicket("SV1234");
            catalog.DeleteTrainTicket("Sofia", "Varna", new DateTime(2015, 1, 28, 7, 45, 00));
            catalog.DeleteBusTicket("Sofia", "Varna", dateTime: new DateTime(2015, 1, 29, 7, 40, 00), travelCompany: "Biomet");
            Assert.AreEqual(0, catalog.GetTicketsCount(TicketType.Air));
            Assert.AreEqual(0, catalog.GetTicketsCount(TicketType.Train));
            Assert.AreEqual(0, catalog.GetTicketsCount(TicketType.Bus));
            var cmdResultFind = catalog.FindTicketsInInterval(new DateTime(1980, 1, 1, 0, 0, 0), new DateTime(2050, 2, 1, 0, 0, 0));
            Assert.AreEqual("Not found", cmdResultFind);
        }