add tests

tests/server/test_logging.py

@@ -0,0 +1,176 @@
+import asyncio
+import logging
+from unittest.mock import AsyncMock, Mock, patch
+
+import pytest
+
+from fastmcp.server.server import FastMCP
+
+
+class CustomLogFormatterForTest(logging.Formatter):
+    def format(self, record: logging.LogRecord) -> str:
+        return f"TEST_FORMAT::{record.levelname}::{record.name}::{record.getMessage()}"
+
+
+@pytest.fixture
+def mcp_server() -> FastMCP:
+    return FastMCP(name="TestLogServer")
+
+
+@patch("fastmcp.server.server.uvicorn.Server")
+@patch("fastmcp.server.server.uvicorn.Config")
+async def test_uvicorn_logging_default_level(
+    mock_uvicorn_config_constructor: Mock,
+    mock_uvicorn_server_constructor: Mock,
+    mcp_server: FastMCP,
+):
+    """Tests that FastMCP passes log_level to uvicorn.Config if no log_config is given."""
+    mock_server_instance = AsyncMock()
+    mock_uvicorn_server_constructor.return_value = mock_server_instance
+    serve_finished_event = asyncio.Event()
+    mock_server_instance.serve.side_effect = serve_finished_event.wait
+
+    test_log_level = "warning"
+
+    server_task = asyncio.create_task(
+        mcp_server.run_http_async(log_level=test_log_level, port=8003)
+    )
+    await asyncio.sleep(0.01)
+
+    mock_uvicorn_config_constructor.assert_called_once()
+    _, kwargs_config = mock_uvicorn_config_constructor.call_args
+
+    assert kwargs_config.get("log_level") == test_log_level.lower()
+    assert "log_config" not in kwargs_config
+
+    mock_uvicorn_server_constructor.assert_called_once_with(
+        mock_uvicorn_config_constructor.return_value
+    )
+    mock_server_instance.serve.assert_awaited_once()
+
+    server_task.cancel()
+    with pytest.raises(asyncio.CancelledError):
+        await server_task
+
+
+@patch("fastmcp.server.server.uvicorn.Server")
+@patch("fastmcp.server.server.uvicorn.Config")
+async def test_uvicorn_logging_with_custom_log_config(
+    mock_uvicorn_config_constructor: Mock,
+    mock_uvicorn_server_constructor: Mock,
+    mcp_server: FastMCP,
+):
+    """Tests that FastMCP passes log_config to uvicorn.Config and not log_level."""
+    mock_server_instance = AsyncMock()
+    mock_uvicorn_server_constructor.return_value = mock_server_instance
+    serve_finished_event = asyncio.Event()
+    mock_server_instance.serve.side_effect = serve_finished_event.wait
+
+    sample_log_config = {
+        "version": 1,
+        "disable_existing_loggers": False,
+        "formatters": {
+            "test_formatter": {
+                "()": "tests.server.test_logging.CustomLogFormatterForTest"
+            }
+        },
+        "handlers": {
+            "test_handler": {
+                "formatter": "test_formatter",
+                "class": "logging.StreamHandler",
+                "stream": "ext://sys.stdout",
+            }
+        },
+        "loggers": {
+            "uvicorn.error": {
+                "handlers": ["test_handler"],
+                "level": "INFO",
+                "propagate": False,
+            }
+        },
+    }
+
+    server_task = asyncio.create_task(
+        mcp_server.run_http_async(
+            uvicorn_config={"log_config": sample_log_config}, port=8004
+        )
+    )
+    await asyncio.sleep(0.01)
+
+    mock_uvicorn_config_constructor.assert_called_once()
+    _, kwargs_config = mock_uvicorn_config_constructor.call_args
+
+    assert kwargs_config.get("log_config") == sample_log_config
+    assert "log_level" not in kwargs_config
+
+    mock_uvicorn_server_constructor.assert_called_once_with(
+        mock_uvicorn_config_constructor.return_value
+    )
+    mock_server_instance.serve.assert_awaited_once()
+
+    server_task.cancel()
+    with pytest.raises(asyncio.CancelledError):
+        await server_task
+
+
+@patch("fastmcp.server.server.uvicorn.Server")
+@patch("fastmcp.server.server.uvicorn.Config")
+async def test_uvicorn_logging_custom_log_config_overrides_log_level_param(
+    mock_uvicorn_config_constructor: Mock,
+    mock_uvicorn_server_constructor: Mock,
+    mcp_server: FastMCP,
+):
+    """Tests log_config precedence if log_level is also passed to run_http_async."""
+    mock_server_instance = AsyncMock()
+    mock_uvicorn_server_constructor.return_value = mock_server_instance
+    serve_finished_event = asyncio.Event()
+    mock_server_instance.serve.side_effect = serve_finished_event.wait
+
+    sample_log_config = {
+        "version": 1,
+        "disable_existing_loggers": False,
+        "formatters": {
+            "test_formatter": {
+                "()": "tests.server.test_logging.CustomLogFormatterForTest"
+            }
+        },
+        "handlers": {
+            "test_handler": {
+                "formatter": "test_formatter",
+                "class": "logging.StreamHandler",
+                "stream": "ext://sys.stdout",
+            }
+        },
+        "loggers": {
+            "uvicorn.error": {
+                "handlers": ["test_handler"],
+                "level": "INFO",
+                "propagate": False,
+            }
+        },
+    }
+    explicit_log_level = "debug"
+
+    server_task = asyncio.create_task(
+        mcp_server.run_http_async(
+            log_level=explicit_log_level,
+            uvicorn_config={"log_config": sample_log_config},
+            port=8005,
+        )
+    )
+    await asyncio.sleep(0.01)
+
+    mock_uvicorn_config_constructor.assert_called_once()
+    _, kwargs_config = mock_uvicorn_config_constructor.call_args
+
+    assert kwargs_config.get("log_config") == sample_log_config
+    assert "log_level" not in kwargs_config
+
+    mock_uvicorn_server_constructor.assert_called_once_with(
+        mock_uvicorn_config_constructor.return_value
+    )
+    mock_server_instance.serve.assert_awaited_once()
+
+    server_task.cancel()
+    with pytest.raises(asyncio.CancelledError):
+        await server_task