diff --git a/tests/schemas/test_stubs.py b/tests/schemas/test_stubs.py
index 5b0c61c..7c729e6 100644
--- a/tests/schemas/test_stubs.py
+++ b/tests/schemas/test_stubs.py
@@ -95,9 +95,22 @@ class TestAddressBookStub:
         assert ab.people is not None
 
 
-# dummy.capnp runtime tests skipped — its annotation imports (c.capnp,
-# c++.capnp) cause pycapnp's C++ SchemaParser to SIGABRT.  The generated
-# .pyi passes static type-checking and `capnp compile -opy` succeeds.
+class TestDummyStub:
+    """dummy.capnp — comprehensive test schema."""
+
+    def test_all_types_loads(self) -> None:
+        from pathlib import Path
+        parser = capnp.SchemaParser()  # pyright: ignore[reportAttributeAccessIssue]
+        m = parser.load(str(Path(__file__).parent / "dummy.capnp"))
+        msg = m.TestAllTypes.new_message(textField="hello", int32Field=42)
+        assert msg.textField == "hello"
+
+    def test_unions(self) -> None:
+        from pathlib import Path
+        parser = capnp.SchemaParser()  # pyright: ignore[reportAttributeAccessIssue]
+        m = parser.load(str(Path(__file__).parent / "dummy.capnp"))
+        u = m.TestUnion.new_message()
+        assert u is not None
 
 
 # Note: multi/consumer.capnp cross-file import test skipped —