Fix backend tests

Signed-off-by: Samuel Monson <[email protected]>

Author: sjmonson

src/guidellm/scheduler/objects.py

@@ -20,6 +20,7 @@
     Protocol,
     TypeVar,
     Union,
+    runtime_checkable,
 )
 
 from pydantic import Field, computed_field
@@ -232,6 +233,7 @@ def model_copy(self, **kwargs) -> ScheduledRequestInfo:  # type: ignore[override
         )
 
 
+@runtime_checkable
 class BackendInterface(Protocol, Generic[RequestT, ResponseT]):
     """
     Abstract interface for request processing backends.

tests/unit/backend/__init__.py renamed to tests/unit/backends/__init__.py

@@ -80,7 +80,7 @@ async def default_model(self) -> str | None:
     def test_class_signatures(self):
         """Test Backend inheritance and type relationships."""
         assert issubclass(Backend, RegistryMixin)
-        assert issubclass(Backend, BackendInterface)
+        assert isinstance(Backend, BackendInterface)
         assert hasattr(Backend, "create")
         assert hasattr(Backend, "register")
         assert hasattr(Backend, "get_registered_object")

tests/unit/backend/test_backend.py renamed to tests/unit/backends/test_backend.py

@@ -397,7 +397,6 @@ def valid_instances(self, request):
     def test_class_signatures(self):
         """Test GenerationRequestTimings inheritance and type relationships."""
         assert issubclass(GenerationRequestTimings, MeasuredRequestTimings)
-        assert issubclass(GenerationRequestTimings, StandardBaseModel)
         assert hasattr(GenerationRequestTimings, "model_dump")
         assert hasattr(GenerationRequestTimings, "model_validate")
 

tests/unit/backend/test_objects.py renamed to tests/unit/backends/test_objects.py

@@ -237,7 +237,7 @@ async def test_info(self):
             target="http://test", model="test-model", timeout=30.0
         )
 
-        info = backend.info()
+        info = backend.info
 
         assert info["target"] == "http://test"
         assert info["model"] == "test-model"
@@ -1074,7 +1074,7 @@ def test_get_chat_message_media_item_jpeg_file(self):
         mock_image = Mock(spec=Image.Image)
         mock_image.tobytes.return_value = b"fake_jpeg_data"
 
-        with patch("guidellm.backend.openai.Image.open", return_value=mock_image):
+        with patch("guidellm.backends.openai.Image.open", return_value=mock_image):
             result = backend._get_chat_message_media_item(mock_jpeg_path)
 
         expected_data = base64.b64encode(b"fake_jpeg_data").decode("utf-8")