diff --git a/tests/integration/test_serializer.py b/tests/integration/test_serializer.py
index 12cbc49..e284091 100644
--- a/tests/integration/test_serializer.py
+++ b/tests/integration/test_serializer.py
@@ -8,10 +8,10 @@
 
 
 @pytest.mark.parametrize("obj", [FooModel(num=42, s="spam", bar=FooModel.Bar(str2int={"eggs": 59}))])
-def test_pydantic_dump_json_load_ok(
-    pydantic_serializer: PydanticSerializer,
+def test_pydantic_dump_json_load_ok[T: BaseModel](
+    pydantic_serializer: PydanticSerializer[T],
     json_serializer: JSONSerializer,
-    message: Message[object],
+    message: Message[T],
     obj: BaseModel,
 ) -> None:
     loaded = json_serializer.load_message(pydantic_serializer.dump_message(message))
@@ -20,10 +20,10 @@ def test_pydantic_dump_json_load_ok(
 
 
 @pytest.fixture
-def pydantic_serializer(obj: BaseModel) -> PydanticSerializer:
+def pydantic_serializer[T: BaseModel](obj: T) -> PydanticSerializer[T]:
     return PydanticSerializer(type(obj))
 
 
 @pytest.fixture
-def message(obj: object, stub_routing_key: str) -> Message[object]:
+def message[T: BaseModel](obj: T, stub_routing_key: str) -> Message[T]:
     return AppMessage(body=obj, routing_key=stub_routing_key)
diff --git a/tests/unit/serializer/test_pydantic.py b/tests/unit/serializer/test_pydantic.py
index a7086de..eedb97b 100644
--- a/tests/unit/serializer/test_pydantic.py
+++ b/tests/unit/serializer/test_pydantic.py
@@ -7,17 +7,17 @@
 
 
 @pytest.mark.parametrize("obj", [FooModel(num=42, s="spam", bar=FooModel.Bar(str2int={"eggs": 59}))])
-def test_dump_load_ok(serializer: PydanticSerializer, message: Message[object]) -> None:
+def test_dump_load_ok[T: BaseModel](serializer: PydanticSerializer[T], message: Message[T]) -> None:
     loaded = serializer.load_message(serializer.dump_message(message))
 
     assert loaded.body == message.body
 
 
 @pytest.fixture
-def serializer(obj: BaseModel) -> PydanticSerializer:
+def serializer[T: BaseModel](obj: T) -> PydanticSerializer[T]:
     return PydanticSerializer(type(obj))
 
 
 @pytest.fixture
-def message(obj: object, stub_routing_key: str) -> Message[object]:
+def message[T: BaseModel](obj: T, stub_routing_key: str) -> Message[T]:
     return AppMessage(body=obj, routing_key=stub_routing_key)