diff --git a/tests/SIGCM2.Api.Tests/Products/ProductPricesAuditFailureTests.cs b/tests/SIGCM2.Api.Tests/Products/ProductPricesAuditFailureTests.cs
new file mode 100644
index 0000000..ccc63e7
--- /dev/null
+++ b/tests/SIGCM2.Api.Tests/Products/ProductPricesAuditFailureTests.cs
@@ -0,0 +1,157 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using System.Text.Json;
+using Dapper;
+using FluentAssertions;
+using Microsoft.Data.SqlClient;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using NSubstitute;
+using NSubstitute.ExceptionExtensions;
+using SIGCM2.Application.Abstractions.Security;
+using SIGCM2.Application.Audit;
+using SIGCM2.Domain.Entities;
+using SIGCM2.TestSupport;
+using Xunit;
+
+namespace SIGCM2.Api.Tests.Products;
+
+/// <summary>
+/// PRD-003 — Batch 7 / T7.4: Audit failure e2e test.
+///
+/// Verifies that when IAuditLogger.LogAsync throws, the TransactionScope rolls back:
+///   - dbo.ProductPrices row is NOT inserted (fail-closed).
+///   - dbo.AuditEvent row is NOT created.
+///   - HTTP response is 500 (unhandled exception propagates through ExceptionFilter).
+///
+/// Uses CreateClientWithOverrides (pattern from issue #36) to inject a throwing IAuditLogger
+/// mock without touching the shared factory.
+///
+/// DB: SIGCM2_Test_Api (ApiIntegration collection).
+/// </summary>
+[Collection("ApiIntegration")]
+public sealed class ProductPricesAuditFailureTests : IAsyncLifetime
+{
+    private const string ConnectionString = TestConnectionStrings.ApiTestDb;
+
+    private readonly TestWebAppFactory _factory;
+    private int _medioId;
+    private int _productTypeId;
+
+    public ProductPricesAuditFailureTests(TestWebAppFactory factory)
+    {
+        _factory = factory;
+    }
+
+    public async Task InitializeAsync()
+    {
+        await using var conn = new SqlConnection(ConnectionString);
+        await conn.OpenAsync();
+
+        _medioId = await conn.QuerySingleAsync<int>(
+            "SELECT TOP 1 Id FROM dbo.Medio WHERE Activo = 1 ORDER BY Id");
+
+        var ptId = await conn.QuerySingleOrDefaultAsync<int?>(
+            "SELECT TOP 1 Id FROM dbo.ProductType WHERE IsActive = 1 ORDER BY Id");
+        if (ptId is null)
+        {
+            ptId = await conn.QuerySingleAsync<int>("""
+                INSERT INTO dbo.ProductType (Nombre, HasDuration, RequiresText, RequiresCategory, IsBundle, AllowImages, IsActive, FechaCreacion)
+                VALUES ('PT_AuditFail_Test', 0, 0, 0, 0, 0, 1, SYSUTCDATETIME());
+                SELECT CAST(SCOPE_IDENTITY() AS INT);
+                """);
+        }
+        _productTypeId = ptId.Value;
+    }
+
+    public Task DisposeAsync() => Task.CompletedTask;
+
+    // ── T7.4 — Audit failure rolls back the ProductPrice insert ──────────────
+
+    [Fact]
+    public async Task PostPrice_WhenAuditLoggerThrows_Returns500AndRollsBackInsert()
+    {
+        // Arrange: seed a unique product
+        var productId = await SeedProductAsync();
+
+        // Count rows before the failing POST
+        await using var conn = new SqlConnection(ConnectionString);
+        await conn.OpenAsync();
+
+        var priceCountBefore = await conn.ExecuteScalarAsync<int>(
+            "SELECT COUNT(1) FROM dbo.ProductPrices WHERE ProductId = @ProductId",
+            new { ProductId = productId });
+
+        var auditCountBefore = await conn.ExecuteScalarAsync<int>(
+            "SELECT COUNT(1) FROM dbo.AuditEvent WHERE Action = 'product_price.created' AND TargetType = 'ProductPrice'");
+
+        // Build a mock IAuditLogger that throws on LogAsync
+        var throwingAuditLogger = Substitute.For<IAuditLogger>();
+        throwingAuditLogger
+            .LogAsync(
+                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(),
+                Arg.Any<object?>(), Arg.Any<CancellationToken>())
+            .ThrowsAsync(new InvalidOperationException("audit down — simulated failure"));
+
+        // Use CreateClientWithOverrides to inject the mock without touching the shared factory
+        using var client = _factory.CreateClientWithOverrides(services =>
+        {
+            services.RemoveAll<IAuditLogger>();
+            services.AddScoped<IAuditLogger>(_ => throwingAuditLogger);
+        });
+
+        // Generate admin token (use factory services, not child)
+        var jwt = _factory.Services.GetRequiredService<IJwtService>();
+        var token = jwt.GenerateAccessToken(new Usuario(
+            id: 1, username: "admin", passwordHash: "x",
+            nombre: "Admin", apellido: "Sys", email: null,
+            rol: "admin", permisosJson: """{"grant":[],"deny":[]}""", activo: true));
+
+        var pvf = DateOnly.FromDateTime(DateTime.UtcNow).AddDays(1).ToString("yyyy-MM-dd");
+
+        var req = new HttpRequestMessage(HttpMethod.Post, $"/api/v1/admin/products/{productId}/prices");
+        req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+        req.Content = JsonContent.Create(new { price = 999m, priceValidFrom = pvf });
+
+        // Act
+        var resp = await client.SendAsync(req);
+
+        // Assert HTTP: audit failure → unhandled exception → 500
+        resp.StatusCode.Should().Be(HttpStatusCode.InternalServerError,
+            because: "IAuditLogger throwing must propagate as 500 (fail-closed)");
+
+        // Assert DB: NO new ProductPrices row was persisted (TransactionScope rolled back)
+        await using var verifyConn = new SqlConnection(ConnectionString);
+        await verifyConn.OpenAsync();
+
+        var priceCountAfter = await verifyConn.ExecuteScalarAsync<int>(
+            "SELECT COUNT(1) FROM dbo.ProductPrices WHERE ProductId = @ProductId",
+            new { ProductId = productId });
+
+        priceCountAfter.Should().Be(priceCountBefore,
+            because: "TransactionScope must roll back the ProductPrices INSERT when audit fails");
+
+        // Assert DB: NO new AuditEvent row for this product
+        var auditCountAfter = await verifyConn.ExecuteScalarAsync<int>(
+            "SELECT COUNT(1) FROM dbo.AuditEvent WHERE Action = 'product_price.created' AND TargetType = 'ProductPrice'");
+
+        auditCountAfter.Should().Be(auditCountBefore,
+            because: "no AuditEvent row must be created when the audit logger throws");
+    }
+
+    // ── Helper: seed an active product ───────────────────────────────────────
+
+    private async Task<int> SeedProductAsync()
+    {
+        await using var conn = new SqlConnection(ConnectionString);
+        await conn.OpenAsync();
+        var nombre = $"PP_AF_{Guid.NewGuid():N}"[..35];
+        return await conn.QuerySingleAsync<int>("""
+            INSERT INTO dbo.Product (Nombre, MedioId, ProductTypeId, BasePrice, PriceDurationDays, IsActive, FechaCreacion)
+            VALUES (@Nombre, @MedioId, @PtId, 100.00, NULL, 1, SYSUTCDATETIME());
+            SELECT CAST(SCOPE_IDENTITY() AS INT);
+            """,
+            new { Nombre = nombre, MedioId = _medioId, PtId = _productTypeId });
+    }
+}
diff --git a/tests/SIGCM2.Application.Tests/Products/Repository/ProductPriceRepositoryIntegrationTests.cs b/tests/SIGCM2.Application.Tests/Products/Repository/ProductPriceRepositoryIntegrationTests.cs
index b18068c..6459f9e 100644
--- a/tests/SIGCM2.Application.Tests/Products/Repository/ProductPriceRepositoryIntegrationTests.cs
+++ b/tests/SIGCM2.Application.Tests/Products/Repository/ProductPriceRepositoryIntegrationTests.cs
@@ -466,6 +466,283 @@ public class ProductPriceRepositoryIntegrationTests : IAsyncLifetime
             "retroactive date behind existing active row triggers SP 50409 → repository maps to ProductPriceForwardOnlyException");
     }
 
+    // ─────────────────────────────────────────────────────────────────────────
+    // Batch 7 — T7.1: Concurrency con 3 tasks + SemaphoreSlim barrier
+    // §REQ-1.2 — Exactamente 1 ganador, 2 perdedores lanzan excepción manejable
+    // ─────────────────────────────────────────────────────────────────────────
+
+    [Fact]
+    public async Task Concurrency_ThreeConcurrentInserts_ExactlyOneSucceeds()
+    {
+        // Barrera: todos esperan en el semáforo; cuando se liberan juntos, la race es auténtica.
+        var barrier = new SemaphoreSlim(0, 3);
+        var pvf = new DateOnly(2027, 6, 1);
+
+        async Task<Exception?> TryInsert(decimal price)
+        {
+            // Cada task espera en la barrera antes de ejecutar
+            await barrier.WaitAsync();
+            try
+            {
+                await using var conn = new SqlConnection(TestConnectionStrings.AppTestDb);
+                await conn.OpenAsync();
+                await ExecAddPriceSpAsync(conn, _defaultProductId, price, pvf);
+                return null; // éxito
+            }
+            catch (SqlException ex)
+            {
+                return ex; // perdedor: 50409, 2601, 2627 o deadlock 1205
+            }
+        }
+
+        var t1 = Task.Run(() => TryInsert(111.00m));
+        var t2 = Task.Run(() => TryInsert(222.00m));
+        var t3 = Task.Run(() => TryInsert(333.00m));
+
+        // Liberar las 3 tasks simultáneamente
+        barrier.Release(3);
+
+        var results = await Task.WhenAll(t1, t2, t3);
+
+        // Exactamente 1 éxito (null), exactamente 2 fallos
+        var successes = results.Count(r => r is null);
+        var failures  = results.Count(r => r is not null);
+
+        successes.Should().Be(1, "exactly one concurrent insert must succeed");
+        failures.Should().Be(2, "the other two must fail with a SqlException");
+
+        // Verificar que el estado final es exactamente 1 activo (PriceValidTo IS NULL)
+        await using var verifyConn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await verifyConn.OpenAsync();
+        var activeCount = await verifyConn.ExecuteScalarAsync<int>(
+            "SELECT COUNT(1) FROM dbo.ProductPrices WHERE ProductId = @ProductId AND PriceValidTo IS NULL",
+            new { ProductId = _defaultProductId });
+
+        activeCount.Should().Be(1, "only one active price (PriceValidTo IS NULL) must survive the race");
+
+        // Sin duplicados: COUNT(*) para este producto debe ser 1 (solo la ganadora)
+        var totalCount = await verifyConn.ExecuteScalarAsync<int>(
+            "SELECT COUNT(1) FROM dbo.ProductPrices WHERE ProductId = @ProductId",
+            new { ProductId = _defaultProductId });
+
+        totalCount.Should().Be(1, "no duplicate rows must exist for the same ProductId");
+    }
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Batch 7 — T7.2: SYSTEM_VERSIONING — no history before close, 1 row after
+    // Verifica que el SP produce exactamente 1 row en dbo.ProductPrices_History
+    // al cerrar el activo, y que antes del cierre la tabla está vacía para ese Id.
+    // ─────────────────────────────────────────────────────────────────────────
+
+    [Fact]
+    public async Task SystemVersioning_BeforeClose_HistoryTableIsEmpty()
+    {
+        await using var conn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await conn.OpenAsync();
+
+        var (firstId, _) = await ExecAddPriceSpAsync(conn, _defaultProductId, 100.00m, new DateOnly(2026, 4, 1));
+
+        // Antes del UPDATE (cierre), history debe estar vacía para este Id
+        var histCountBefore = await conn.ExecuteScalarAsync<int>(
+            "SELECT COUNT(1) FROM dbo.ProductPrices_History WHERE Id = @Id",
+            new { Id = firstId });
+
+        histCountBefore.Should().Be(0,
+            "SYSTEM_VERSIONING only creates history rows on UPDATE/DELETE, not on INSERT");
+    }
+
+    [Fact]
+    public async Task SystemVersioning_AfterClose_ExactlyOneHistoryRow()
+    {
+        await using var conn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await conn.OpenAsync();
+
+        var (firstId, _) = await ExecAddPriceSpAsync(conn, _defaultProductId, 100.00m, new DateOnly(2026, 4, 1));
+
+        // Cierra el activo con una segunda inserción más futura
+        await ExecAddPriceSpAsync(conn, _defaultProductId, 200.00m, new DateOnly(2026, 4, 20));
+
+        // dbo.ProductPrices_History debe tener exactamente 1 row para el Id cerrado
+        var histCount = await conn.ExecuteScalarAsync<int>(
+            "SELECT COUNT(1) FROM dbo.ProductPrices_History WHERE Id = @Id",
+            new { Id = firstId });
+
+        histCount.Should().Be(1,
+            "SYSTEM_VERSIONING must produce exactly one history row when the active price is closed via UPDATE");
+
+        // El row activo en dbo.ProductPrices debe tener PriceValidTo <> NULL
+        var pvt = await conn.ExecuteScalarAsync<DateTime?>(
+            "SELECT PriceValidTo FROM dbo.ProductPrices WHERE Id = @Id",
+            new { Id = firstId });
+
+        pvt.Should().NotBeNull("the closed row in dbo.ProductPrices must have PriceValidTo set");
+        pvt!.Value.Date.Should().Be(new DateTime(2026, 4, 19),
+            "PriceValidTo = new PVF - 1 day = 2026-04-19");
+    }
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Batch 7 — T7.3: FOR SYSTEM_TIME AS OF — snapshot temporal
+    // Verifica que la history table preserva el estado del activo en el instante
+    // pre-cierre y que la query temporal devuelve el precio correcto.
+    // ─────────────────────────────────────────────────────────────────────────
+
+    [Fact]
+    public async Task ForSystemTimeAsOf_ReturnsSnapshotAtT0()
+    {
+        await using var conn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await conn.OpenAsync();
+
+        // T0: insertar precio1 y capturar el instante UTC antes de cerrarlo
+        var (firstId, _) = await ExecAddPriceSpAsync(conn, _defaultProductId, 100.00m, new DateOnly(2026, 4, 1));
+
+        // Capturar T0 inmediatamente después del INSERT (SYSTEM_VERSIONING usa DATETIME2 UTC)
+        var t0 = await conn.ExecuteScalarAsync<DateTime>(
+            "SELECT SYSUTCDATETIME()");
+
+        // Esperar 200ms para que DATETIME2(3) avance y el registro de history tenga un rango claro
+        await Task.Delay(200);
+
+        // Insertar precio2 que cierra precio1 — esto produce el row en history
+        await ExecAddPriceSpAsync(conn, _defaultProductId, 200.00m, new DateOnly(2026, 5, 1));
+
+        // T7.3.a — Query FOR SYSTEM_TIME AS OF T0: debe devolver precio1 con PriceValidTo = NULL
+        // (estado del registro tal como estaba en T0, antes del cierre)
+        var snapshotRow = await conn.QuerySingleOrDefaultAsync<dynamic>(
+            """
+            SELECT Id, Price, PriceValidTo
+            FROM dbo.ProductPrices
+            FOR SYSTEM_TIME AS OF @T0
+            WHERE ProductId = @ProductId
+              AND Id = @Id
+            """,
+            new { T0 = t0, ProductId = _defaultProductId, Id = firstId });
+
+        ((object?)snapshotRow).Should().NotBeNull(
+            "FOR SYSTEM_TIME AS OF T0 must return the row as it existed at T0 (before close)");
+        ((decimal)snapshotRow!.Price).Should().Be(100.00m);
+        ((object?)snapshotRow.PriceValidTo).Should().BeNull(
+            "at T0 the row was still active (PriceValidTo IS NULL)");
+
+        // T7.3.b — Query actual (sin FOR SYSTEM_TIME): precio1 debe tener PriceValidTo != NULL
+        var currentRow = await conn.QuerySingleOrDefaultAsync<dynamic>(
+            "SELECT Id, Price, PriceValidTo FROM dbo.ProductPrices WHERE Id = @Id",
+            new { Id = firstId });
+
+        ((object?)currentRow).Should().NotBeNull();
+        ((object?)currentRow!.PriceValidTo).Should().NotBeNull(
+            "in current state, the first price is closed (PriceValidTo IS NOT NULL)");
+    }
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Batch 7 — T7.5: GetActiveAsync boundary cases (ventanas civiles inclusivas)
+    // §REQ-4.4 — Inclusive en ambos extremos (PVF y PVT)
+    // ─────────────────────────────────────────────────────────────────────────
+
+    [Fact]
+    public async Task GetActiveAsync_BeforeFirstPrice_ReturnsNull()
+    {
+        await using var seedConn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await seedConn.OpenAsync();
+
+        // Precio1: [2026-01-01 .. 2026-03-31] (cerrado)
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 100.00m, new DateOnly(2026, 1, 1));
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 150.00m, new DateOnly(2026, 4, 1));
+
+        var repo = BuildRepository();
+        var result = await repo.GetActiveAsync(_defaultProductId, new DateOnly(2025, 12, 31));
+
+        result.Should().BeNull("date is before the first PriceValidFrom");
+    }
+
+    [Fact]
+    public async Task GetActiveAsync_ExactMatchPvf_ReturnsPrice()
+    {
+        await using var seedConn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await seedConn.OpenAsync();
+
+        // Precio1: [2026-01-01 .. 2026-03-31]
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 100.00m, new DateOnly(2026, 1, 1));
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 150.00m, new DateOnly(2026, 4, 1));
+
+        var repo = BuildRepository();
+        // Exact match en PVF
+        var result = await repo.GetActiveAsync(_defaultProductId, new DateOnly(2026, 1, 1));
+
+        result.Should().NotBeNull("date equals PriceValidFrom → inclusive lower bound");
+        result!.Price.Should().Be(100.00m);
+    }
+
+    [Fact]
+    public async Task GetActiveAsync_MiddleOfRange_ReturnsPrice()
+    {
+        await using var seedConn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await seedConn.OpenAsync();
+
+        // Precio1: [2026-01-01 .. 2026-03-31], Precio2: [2026-04-01 ..]
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 100.00m, new DateOnly(2026, 1, 1));
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 150.00m, new DateOnly(2026, 4, 1));
+
+        var repo = BuildRepository();
+        var result = await repo.GetActiveAsync(_defaultProductId, new DateOnly(2026, 2, 15));
+
+        result.Should().NotBeNull("date is in the middle of precio1 window");
+        result!.Price.Should().Be(100.00m);
+    }
+
+    [Fact]
+    public async Task GetActiveAsync_ExactMatchPvt_ReturnsClosedPrice()
+    {
+        await using var seedConn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await seedConn.OpenAsync();
+
+        // Precio1: [2026-01-01 .. 2026-03-31] — PVT=2026-03-31 (día anterior a 2026-04-01)
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 100.00m, new DateOnly(2026, 1, 1));
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 150.00m, new DateOnly(2026, 4, 1));
+
+        var repo = BuildRepository();
+        // Exact match en PVT del precio1 → inclusive upper bound
+        var result = await repo.GetActiveAsync(_defaultProductId, new DateOnly(2026, 3, 31));
+
+        result.Should().NotBeNull("date equals PriceValidTo → inclusive upper bound");
+        result!.Price.Should().Be(100.00m);
+    }
+
+    [Fact]
+    public async Task GetActiveAsync_ExactMatchNextPvf_ReturnsNextPrice()
+    {
+        await using var seedConn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await seedConn.OpenAsync();
+
+        // Precio1: [2026-01-01 .. 2026-03-31], Precio2: [2026-04-01 ..]
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 100.00m, new DateOnly(2026, 1, 1));
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 150.00m, new DateOnly(2026, 4, 1));
+
+        var repo = BuildRepository();
+        // PVF del precio2 → debe devolver precio2
+        var result = await repo.GetActiveAsync(_defaultProductId, new DateOnly(2026, 4, 1));
+
+        result.Should().NotBeNull("date equals PriceValidFrom of precio2 → inclusive lower bound");
+        result!.Price.Should().Be(150.00m);
+    }
+
+    [Fact]
+    public async Task GetActiveAsync_FarFuture_ReturnsActivePrice()
+    {
+        await using var seedConn = new SqlConnection(TestConnectionStrings.AppTestDb);
+        await seedConn.OpenAsync();
+
+        // Solo precio activo desde 2026-04-01 (PriceValidTo = NULL)
+        await ExecAddPriceSpAsync(seedConn, _defaultProductId, 200.00m, new DateOnly(2026, 4, 1));
+
+        var repo = BuildRepository();
+        var result = await repo.GetActiveAsync(_defaultProductId, new DateOnly(2099, 12, 31));
+
+        result.Should().NotBeNull("far-future date should return the open-ended active price");
+        result!.Price.Should().Be(200.00m);
+        result.IsActive.Should().BeTrue();
+        result.PriceValidTo.Should().BeNull();
+    }
+
     // ── Helper: build a real ProductPriceRepository using the test DB ─────────
 
     private static ProductPriceRepository BuildRepository()