feat(application): Product handlers + DI registration, fix permiso count to 27 (PRD-002)

tests/SIGCM2.Application.Tests/Products/GetById/GetProductByIdQueryHandlerTests.cs

@@ -0,0 +1,60 @@
+using FluentAssertions;
+using NSubstitute;
+using SIGCM2.Application.Abstractions.Persistence;
+using SIGCM2.Application.Products.GetById;
+using SIGCM2.Domain.Entities;
+using SIGCM2.Domain.Exceptions;
+
+namespace SIGCM2.Application.Tests.Products.GetById;
+
+/// <summary>
+/// PRD-002 — GetProductByIdQueryHandler tests.
+/// </summary>
+public class GetProductByIdQueryHandlerTests
+{
+    private readonly IProductRepository _repo = Substitute.For<IProductRepository>();
+    private readonly GetProductByIdQueryHandler _handler;
+
+    public GetProductByIdQueryHandlerTests()
+    {
+        _handler = new GetProductByIdQueryHandler(_repo);
+    }
+
+    private static Product AProduct(int id = 1) => new(
+        id: id,
+        nombre: "Clasificado Estándar",
+        medioId: 1,
+        productTypeId: 2,
+        rubroId: null,
+        basePrice: 100.50m,
+        priceDurationDays: null,
+        isActive: true,
+        fechaCreacion: new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc),
+        fechaModificacion: null);
+
+    [Fact]
+    public async Task Handle_ExistingId_ReturnsMappedDto()
+    {
+        _repo.GetByIdAsync(1, Arg.Any<CancellationToken>()).Returns(AProduct(1));
+
+        var result = await _handler.Handle(new GetProductByIdQuery(1));
+
+        result.Id.Should().Be(1);
+        result.Nombre.Should().Be("Clasificado Estándar");
+        result.MedioId.Should().Be(1);
+        result.ProductTypeId.Should().Be(2);
+        result.BasePrice.Should().Be(100.50m);
+        result.IsActive.Should().BeTrue();
+    }
+
+    [Fact]
+    public async Task Handle_NotFound_ThrowsProductNotFoundException()
+    {
+        _repo.GetByIdAsync(99, Arg.Any<CancellationToken>()).Returns((Product?)null);
+
+        var act = async () => await _handler.Handle(new GetProductByIdQuery(99));
+
+        await act.Should().ThrowAsync<ProductNotFoundException>()
+            .Where(e => e.ProductId == 99);
+    }
+}