public void AddEntity() { using (var context = new DataContext()) { IRepository <Dock> dockRepository = new DockRepository(context); IRepository <Engineer> engineerRepository = new EngineerRepository(context); IRepository <Pilot> pilotRepository = new PilotRepository(context); IRepository <Ship> shipRepository = new ShipRepository(context); IRepository <Station> stationRepository = new StationRepository(context); var station = new Station { Name = StationName, Location = StationLocation }; var dock = new Dock { Name = "First dock", CountOfShipsPlaces = 3 }; var engineer = new Engineer { FirstName = "Ivan", MiddleName = "Ivanovich", LastName = "Ivanov", Biography = "Very powerfully engineer", Qualification = "Welder" }; var pilot = new Pilot { FirstName = "Raman", MiddleName = "Igorevich", LastName = "Dzianishchyk", Biography = "Born in bla-bla-bla-blar", ExperienceFlights = 3 }; var ship = new Ship { Name = "Impetuous" }; station.Docks = new List <Dock>() { dock }; station.Engineers = new List <Engineer>() { engineer }; pilot.OwnShip = ship; ship.DockRegistry = dock; dock.Engineers = new List <Engineer>() { engineer }; stationRepository.Add(station); dockRepository.Add(dock); engineerRepository.Add(engineer); pilotRepository.Add(pilot); shipRepository.Add(ship); Assert.IsTrue( stationRepository.Count(null) > 0 && shipRepository.Count(null) > 0 && pilotRepository.Count(null) > 0 && engineerRepository.Count(null) > 0 && dockRepository.Count(null) > 0); } }