classlib/ExpenseTracker.Application/Transactions/Commands/Delete/DeleteTransactionCommandValidator.cs

using FluentValidation;

namespace ExpenseTracker.Application.Transactions.Commands.Delete;

public class DeleteTransactionCommandValidator : AbstractValidator<DeleteTransactionCommand>
{
    public DeleteTransactionCommandValidator()
    {
        RuleFor(e => e.Id)
            .NotEmpty();
    }
}