public TypeOfIngredient Add(TypeOfIngredient item)
 {
     var newTypeOfIngredient = (TypeOfIngredient)item.Clone();
     newTypeOfIngredient.Id = !_types.Any() ? 1 : _types.Max(rate => rate.Id) + 1;
     _types.Add(newTypeOfIngredient);
     return (TypeOfIngredient)newTypeOfIngredient.Clone();
 }
 public TypeOfIngredient Update(TypeOfIngredient item)
 {
     var existTypeOfIngredient = _types.SingleOrDefault(type => type.Id == item.Id);
     if (existTypeOfIngredient == null)
     {
         throw new NullReferenceException();
     }
     existTypeOfIngredient.Name = item.Name;
     return (TypeOfIngredient)existTypeOfIngredient.Clone();
 }
 public void AddTest()
 {
     var name = Guid.NewGuid().ToString();
     var newTypeOfIngredient = new TypeOfIngredient
     {
         Name = name
     };
     var AddedTypeOfIngredient = service.Add(newTypeOfIngredient);
     Assert.IsNotNull(AddedTypeOfIngredient);
     Assert.IsTrue(AddedTypeOfIngredient.Id > 0);
     Assert.AreEqual(AddedTypeOfIngredient.Name, name);
 }