SIG-CM2.0/tests/SIGCM2.Application.Tests/PuntosDeVenta/Reservar/ReservarNumeroCommandHandlerTests.cs

using NSubstitute;
using NSubstitute.ExceptionExtensions;
using SIGCM2.Application.Abstractions.Persistence;
using SIGCM2.Application.PuntosDeVenta.Reservar;
using SIGCM2.Domain.Enums;
using SIGCM2.Domain.Exceptions;

namespace SIGCM2.Application.Tests.PuntosDeVenta.Reservar;

public class ReservarNumeroCommandHandlerTests
{
    private readonly IPuntoDeVentaRepository _repo = Substitute.For<IPuntoDeVentaRepository>();
    private readonly ReservarNumeroCommandHandler _handler;

    private static readonly ReservarNumeroCommand ValidCommand =
        new(PuntoDeVentaId: 10, TipoComprobante: TipoComprobante.FacturaA);

    public ReservarNumeroCommandHandlerTests()
    {
        // Use delay = 0 for fast tests
        _handler = new ReservarNumeroCommandHandler(_repo, deadlockBackoffMs: [0, 0, 0]);
    }

    // ── happy path ───────────────────────────────────────────────────────────

    [Fact]
    public async Task Handle_HappyPath_ReturnsNumeroReservado()
    {
        _repo.ReservarNumeroAsync(10, TipoComprobante.FacturaA, Arg.Any<CancellationToken>())
             .Returns(7);

        var result = await _handler.Handle(ValidCommand);

        Assert.Equal(TipoComprobante.FacturaA, result.TipoComprobante);
        Assert.Equal(7, result.NumeroReservado);
    }

    // ── retry deadlock ────────────────────────────────────────────────────────

    [Fact]
    public async Task Handle_DeadlockTwiceThenSucceeds_ReturnsResult()
    {
        var deadlock = new DeadlockTransientException();

        _repo.ReservarNumeroAsync(10, TipoComprobante.FacturaA, Arg.Any<CancellationToken>())
             .Returns(
                 _ => Task.FromException<int>(deadlock),
                 _ => Task.FromException<int>(deadlock),
                 _ => Task.FromResult(3));

        var result = await _handler.Handle(ValidCommand);

        Assert.Equal(3, result.NumeroReservado);
    }

    [Fact]
    public async Task Handle_DeadlockThreeTimes_BubblesUpDeadlockException()
    {
        var deadlock = new DeadlockTransientException();

        _repo.ReservarNumeroAsync(10, TipoComprobante.FacturaA, Arg.Any<CancellationToken>())
             .Returns(
                 _ => Task.FromException<int>(deadlock),
                 _ => Task.FromException<int>(deadlock),
                 _ => Task.FromException<int>(deadlock));

        await Assert.ThrowsAsync<DeadlockTransientException>(
            () => _handler.Handle(ValidCommand));
    }

    [Fact]
    public async Task Handle_DeadlockExhaustsBackoff_TriedFourTimesTotal()
    {
        // backoff = [0,0,0] → 3 retries → 4 total attempts (1 initial + 3 retries)
        var deadlock = new DeadlockTransientException();

        _repo.ReservarNumeroAsync(10, TipoComprobante.FacturaA, Arg.Any<CancellationToken>())
             .Returns(_ => Task.FromException<int>(deadlock));

        try { await _handler.Handle(ValidCommand); } catch (DeadlockTransientException) { }

        await _repo.Received(4).ReservarNumeroAsync(
            Arg.Any<int>(), Arg.Any<TipoComprobante>(), Arg.Any<CancellationToken>());
    }

    // ── domain exceptions bubble up without retry ─────────────────────────────

    [Fact]
    public async Task Handle_PuntoDeVentaInactivo_BubblesUpImmediately()
    {
        _repo.ReservarNumeroAsync(10, TipoComprobante.FacturaA, Arg.Any<CancellationToken>())
             .Throws(new PuntoDeVentaInactivoException(10));

        await Assert.ThrowsAsync<PuntoDeVentaInactivoException>(
            () => _handler.Handle(ValidCommand));

        await _repo.Received(1).ReservarNumeroAsync(
            Arg.Any<int>(), Arg.Any<TipoComprobante>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task Handle_MedioInactivo_BubblesUpImmediately()
    {
        _repo.ReservarNumeroAsync(10, TipoComprobante.FacturaA, Arg.Any<CancellationToken>())
             .Throws(new MedioInactivoException(5));

        await Assert.ThrowsAsync<MedioInactivoException>(
            () => _handler.Handle(ValidCommand));

        await _repo.Received(1).ReservarNumeroAsync(
            Arg.Any<int>(), Arg.Any<TipoComprobante>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task Handle_PdvNotFound_BubblesUpImmediately()
    {
        _repo.ReservarNumeroAsync(10, TipoComprobante.FacturaA, Arg.Any<CancellationToken>())
             .Throws(new PuntoDeVentaNotFoundException(10));

        await Assert.ThrowsAsync<PuntoDeVentaNotFoundException>(
            () => _handler.Handle(ValidCommand));

        await _repo.Received(1).ReservarNumeroAsync(
            Arg.Any<int>(), Arg.Any<TipoComprobante>(), Arg.Any<CancellationToken>());
    }
}