ANTOOZA-BACKEND/Tests/Application.Tests/WalletBalanceConcurrencyTests.cs

using Domain.Entities.Common.ValueObject;
using Domain.Entities.Wallets;
using Microsoft.EntityFrameworkCore;

namespace Application.Tests;

[TestClass]
public sealed class WalletBalanceConcurrencyTests
{
    [TestMethod]
    public async Task ConcurrentUpdate_OnSameBalance_ThrowsConcurrencyException()
    {
        // P0 #8 재현: WalletBalance 에 동시성 토큰이 없어 동시 갱신이 last-write-wins 로
        // 조용히 덮어써졌다 (이중 지출 가능). 기대 행위: 두 번째 저장은 DbUpdateConcurrencyException.
        int memberID;
        using (var setup = TestDb.Create())
        {
            memberID = await TestDb.CreateMemberAsync(setup);
            var wallet = Wallet.Create(memberID);
            wallet.CreditPgCharge(Money.KRW(10000), "seed");
            await setup.Wallet.AddAsync(wallet);
            await setup.SaveChangesAsync(default);
        }

        using var db1 = TestDb.Create();
        using var db2 = TestDb.Create();
        var w1 = await db1.Wallet.Include(w => w.Balances).AsSplitQuery().SingleAsync(w => w.MemberID == memberID);
        var w2 = await db2.Wallet.Include(w => w.Balances).AsSplitQuery().SingleAsync(w => w.MemberID == memberID);

        w1.CreditPgCharge(Money.KRW(1000), "c1");
        w2.CreditPgCharge(Money.KRW(1000), "c2");

        await db1.SaveChangesAsync(default);

        await Assert.ThrowsExceptionAsync<DbUpdateConcurrencyException>(() => db2.SaveChangesAsync(default));
    }
}