diff --git a/tests/SIGCM2.Application.Tests/Domain/Fiscal/FiscalExceptionsTests.cs b/tests/SIGCM2.Application.Tests/Domain/Fiscal/FiscalExceptionsTests.cs
new file mode 100644
index 0000000..b8a5069
--- /dev/null
+++ b/tests/SIGCM2.Application.Tests/Domain/Fiscal/FiscalExceptionsTests.cs
@@ -0,0 +1,99 @@
+using FluentAssertions;
+using SIGCM2.Domain.Exceptions;
+using SIGCM2.Domain.Fiscal;
+
+namespace SIGCM2.Application.Tests.Domain.Fiscal;
+
+public class FiscalExceptionsTests
+{
+    // ── T200.30: cada excepción instancia correctamente con mensaje ───────────
+
+    [Fact]
+    public void PorcentajeInmutableException_HasExpectedMessage()
+    {
+        var ex = new PorcentajeInmutableException();
+
+        ex.Message.Should().Contain("inmutable");
+        ex.Message.Should().Contain("nueva versión");
+        ex.Message.Should().Contain("/iva/");
+    }
+
+    [Fact]
+    public void AlicuotaInmutableException_HasExpectedMessage()
+    {
+        var ex = new AlicuotaInmutableException();
+
+        ex.Message.Should().Contain("inmutable");
+        ex.Message.Should().Contain("nueva versión");
+        ex.Message.Should().Contain("/iibb/");
+    }
+
+    [Fact]
+    public void PredecesorYaCerradoException_ContainsId()
+    {
+        var ex = new PredecesorYaCerradoException(42);
+
+        ex.PredecesorId.Should().Be(42);
+        ex.Message.Should().Contain("42");
+    }
+
+    [Fact]
+    public void DuplicateCodigoException_ContainsCodigo()
+    {
+        var ex = new DuplicateCodigoException("IVA_21");
+
+        ex.Codigo.Should().Be("IVA_21");
+        ex.Message.Should().Contain("IVA_21");
+    }
+
+    [Fact]
+    public void DuplicateProvinciaException_ContainsProvincia()
+    {
+        var ex = new DuplicateProvinciaException(ProvinciaArgentina.Cordoba);
+
+        ex.Provincia.Should().Be(ProvinciaArgentina.Cordoba);
+        ex.Message.Should().Contain("Cordoba");
+    }
+
+    // ── Todas heredan de DomainException ─────────────────────────────────────
+
+    [Fact]
+    public void PorcentajeInmutableException_InheritsFromDomainException()
+    {
+        var ex = new PorcentajeInmutableException();
+
+        ex.Should().BeAssignableTo<DomainException>();
+    }
+
+    [Fact]
+    public void AlicuotaInmutableException_InheritsFromDomainException()
+    {
+        var ex = new AlicuotaInmutableException();
+
+        ex.Should().BeAssignableTo<DomainException>();
+    }
+
+    [Fact]
+    public void PredecesorYaCerradoException_InheritsFromDomainException()
+    {
+        var ex = new PredecesorYaCerradoException(1);
+
+        ex.Should().BeAssignableTo<DomainException>();
+    }
+
+    [Fact]
+    public void DuplicateCodigoException_InheritsFromDomainException()
+    {
+        var ex = new DuplicateCodigoException("X");
+
+        ex.Should().BeAssignableTo<DomainException>();
+    }
+
+    [Fact]
+    public void DuplicateProvinciaException_InheritsFromDomainException()
+    {
+        var ex = new DuplicateProvinciaException(ProvinciaArgentina.Salta);
+
+        ex.Should().BeAssignableTo<DomainException>();
+    }
+}