public void Should_NotAddCarn_When_TheWagonAlreadyHasAnCarn() { //Arrange train.AddAnimalToTrain(AnimalType.Carnivore, AnimalSize.Small); train.AddAnimalToTrain(AnimalType.Carnivore, AnimalSize.Small); train.AddAnimalToTrain(AnimalType.Carnivore, AnimalSize.Small); train.AddAnimalToTrain(AnimalType.Carnivore, AnimalSize.Small); train.AddAnimalToTrain(AnimalType.Carnivore, AnimalSize.Small); train.AddAnimalToTrain(AnimalType.Carnivore, AnimalSize.Big); train.AddAnimalsToWagons(); //Act foreach (Wagon wagon in train.LoadWagons()) { int carnivoresInWagon = 0; foreach (Animal animal in wagon.Animals) { if (animal.FoodType == AnimalType.Carnivore) { carnivoresInWagon += 1; } } //Assert Assert.IsFalse(carnivoresInWagon > 1); } }