public void ShouldDetectInvalidJourney()
{
IPort portBuenosAires = _portRepository.GetPort("Buenos Aires");
IPort portNy = _portRepository.GetPort("New York");
IPort portLiverpool = _portRepository.GetPort("Liverpool");
IPort portCapetown = _portRepository.GetPort("Cape Town");
IPort portCasablanca = _portRepository.GetPort("Casablanca");
var invalidJourney = new Journey <IPort>(_routeRepository).WithPort(portBuenosAires).WithPort(portCapetown).WithPort(portCasablanca);
var validJourney = new Journey <IPort>(_routeRepository).WithPort(portBuenosAires).WithPort(portNy).WithPort(portLiverpool);
Assert.IsFalse(invalidJourney.IsValid());
Assert.IsTrue(validJourney.IsValid());
}