in src/app/ContosoTraders.Api.Core/Requests/Validators/UpdateCartItemQuantityRequestValidator.cs [5:20]
public UpdateCartItemQuantityRequestValidator()
{
RuleFor(request => request)
.NotNull();
RuleFor(request => request.CartItem)
.NotNull();
RuleFor(request => request.CartItem.CartItemId)
.NotNull()
.WithMessage("CartItemId cannot be null/empty.");
RuleFor(request => request.CartItem.Quantity)
.NotNull()
.WithMessage("Quantity cannot be null/empty.");
}