[Core] Support load and unload LoRA in api server (#6566)

Co-authored-by: Jee Jee Li <pandaleefree@gmail.com>

tests/entrypoints/openai/test_serving_engine.py

@@ -0,0 +1,107 @@
+from http import HTTPStatus
+from unittest.mock import MagicMock
+
+import pytest
+
+from vllm.config import ModelConfig
+from vllm.engine.protocol import AsyncEngineClient
+from vllm.entrypoints.openai.protocol import (ErrorResponse,
+                                              LoadLoraAdapterRequest,
+                                              UnloadLoraAdapterRequest)
+from vllm.entrypoints.openai.serving_engine import OpenAIServing
+
+MODEL_NAME = "meta-llama/Llama-2-7b"
+LORA_LOADING_SUCCESS_MESSAGE = (
+    "Success: LoRA adapter '{lora_name}' added successfully.")
+LORA_UNLOADING_SUCCESS_MESSAGE = (
+    "Success: LoRA adapter '{lora_name}' removed successfully.")
+
+
+async def _async_serving_engine_init():
+    mock_engine_client = MagicMock(spec=AsyncEngineClient)
+    mock_model_config = MagicMock(spec=ModelConfig)
+    # Set the max_model_len attribute to avoid missing attribute
+    mock_model_config.max_model_len = 2048
+
+    serving_engine = OpenAIServing(mock_engine_client,
+                                   mock_model_config,
+                                   served_model_names=[MODEL_NAME],
+                                   lora_modules=None,
+                                   prompt_adapters=None,
+                                   request_logger=None)
+    return serving_engine
+
+
+@pytest.mark.asyncio
+async def test_load_lora_adapter_success():
+    serving_engine = await _async_serving_engine_init()
+    request = LoadLoraAdapterRequest(lora_name="adapter",
+                                     lora_path="/path/to/adapter2")
+    response = await serving_engine.load_lora_adapter(request)
+    assert response == LORA_LOADING_SUCCESS_MESSAGE.format(lora_name='adapter')
+    assert len(serving_engine.lora_requests) == 1
+    assert serving_engine.lora_requests[0].lora_name == "adapter"
+
+
+@pytest.mark.asyncio
+async def test_load_lora_adapter_missing_fields():
+    serving_engine = await _async_serving_engine_init()
+    request = LoadLoraAdapterRequest(lora_name="", lora_path="")
+    response = await serving_engine.load_lora_adapter(request)
+    assert isinstance(response, ErrorResponse)
+    assert response.type == "InvalidUserInput"
+    assert response.code == HTTPStatus.BAD_REQUEST
+
+
+@pytest.mark.asyncio
+async def test_load_lora_adapter_duplicate():
+    serving_engine = await _async_serving_engine_init()
+    request = LoadLoraAdapterRequest(lora_name="adapter1",
+                                     lora_path="/path/to/adapter1")
+    response = await serving_engine.load_lora_adapter(request)
+    assert response == LORA_LOADING_SUCCESS_MESSAGE.format(
+        lora_name='adapter1')
+    assert len(serving_engine.lora_requests) == 1
+
+    request = LoadLoraAdapterRequest(lora_name="adapter1",
+                                     lora_path="/path/to/adapter1")
+    response = await serving_engine.load_lora_adapter(request)
+    assert isinstance(response, ErrorResponse)
+    assert response.type == "InvalidUserInput"
+    assert response.code == HTTPStatus.BAD_REQUEST
+    assert len(serving_engine.lora_requests) == 1
+
+
+@pytest.mark.asyncio
+async def test_unload_lora_adapter_success():
+    serving_engine = await _async_serving_engine_init()
+    request = LoadLoraAdapterRequest(lora_name="adapter1",
+                                     lora_path="/path/to/adapter1")
+    response = await serving_engine.load_lora_adapter(request)
+    assert len(serving_engine.lora_requests) == 1
+
+    request = UnloadLoraAdapterRequest(lora_name="adapter1")
+    response = await serving_engine.unload_lora_adapter(request)
+    assert response == LORA_UNLOADING_SUCCESS_MESSAGE.format(
+        lora_name='adapter1')
+    assert len(serving_engine.lora_requests) == 0
+
+
+@pytest.mark.asyncio
+async def test_unload_lora_adapter_missing_fields():
+    serving_engine = await _async_serving_engine_init()
+    request = UnloadLoraAdapterRequest(lora_name="", lora_int_id=None)
+    response = await serving_engine.unload_lora_adapter(request)
+    assert isinstance(response, ErrorResponse)
+    assert response.type == "InvalidUserInput"
+    assert response.code == HTTPStatus.BAD_REQUEST
+
+
+@pytest.mark.asyncio
+async def test_unload_lora_adapter_not_found():
+    serving_engine = await _async_serving_engine_init()
+    request = UnloadLoraAdapterRequest(lora_name="nonexistent_adapter")
+    response = await serving_engine.unload_lora_adapter(request)
+    assert isinstance(response, ErrorResponse)
+    assert response.type == "InvalidUserInput"
+    assert response.code == HTTPStatus.BAD_REQUEST