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chore: import upstream snapshot with attribution
2026-07-13 12:10:27 +08:00

264 lines
7.8 KiB
Python

import threading
import anyio
import anyio.from_thread
import pytest
from inline_snapshot import snapshot
from mcp_types import InputRequiredResult
from pydantic import BaseModel
from mcp.server.mcpserver.resources import FunctionResource
class TestFunctionResource:
"""Test FunctionResource functionality."""
def test_function_resource_creation(self):
"""Test creating a FunctionResource."""
def my_func() -> str: # pragma: no cover
return "test content"
resource = FunctionResource(
uri="fn://test",
name="test",
description="test function",
fn=my_func,
)
assert str(resource.uri) == "fn://test"
assert resource.name == "test"
assert resource.description == "test function"
assert resource.mime_type == "text/plain" # default
assert resource.fn == my_func
@pytest.mark.anyio
async def test_read_text(self):
"""Test reading text from a FunctionResource."""
def get_data() -> str:
return "Hello, world!"
resource = FunctionResource(
uri="function://test",
name="test",
fn=get_data,
)
content = await resource.read()
assert content == "Hello, world!"
assert resource.mime_type == "text/plain"
@pytest.mark.anyio
async def test_read_binary(self):
"""Test reading binary data from a FunctionResource."""
def get_data() -> bytes:
return b"Hello, world!"
resource = FunctionResource(
uri="function://test",
name="test",
fn=get_data,
)
content = await resource.read()
assert content == b"Hello, world!"
@pytest.mark.anyio
async def test_json_conversion(self):
"""Test automatic JSON conversion of non-string results."""
def get_data() -> dict[str, str]:
return {"key": "value"}
resource = FunctionResource(
uri="function://test",
name="test",
fn=get_data,
)
content = await resource.read()
assert isinstance(content, str)
assert '"key": "value"' in content
@pytest.mark.anyio
async def test_error_handling(self):
"""Test error handling in FunctionResource."""
def failing_func() -> str:
raise ValueError("Test error")
resource = FunctionResource(
uri="function://test",
name="test",
fn=failing_func,
)
with pytest.raises(ValueError, match="Error reading resource function://test"):
await resource.read()
@pytest.mark.anyio
async def test_basemodel_conversion(self):
"""Test handling of BaseModel types."""
class MyModel(BaseModel):
name: str
resource = FunctionResource(
uri="function://test",
name="test",
fn=lambda: MyModel(name="test"),
)
content = await resource.read()
assert content == '{\n "name": "test"\n}'
@pytest.mark.anyio
async def test_custom_type_conversion(self):
"""Test handling of custom types."""
class CustomData:
def __str__(self) -> str:
return "custom data"
def get_data() -> CustomData:
return CustomData()
resource = FunctionResource(
uri="function://test",
name="test",
fn=get_data,
)
content = await resource.read()
assert isinstance(content, str)
@pytest.mark.anyio
async def test_async_read_text(self):
"""Test reading text from async FunctionResource."""
async def get_data() -> str:
return "Hello, world!"
resource = FunctionResource(
uri="function://test",
name="test",
fn=get_data,
)
content = await resource.read()
assert content == "Hello, world!"
assert resource.mime_type == "text/plain"
@pytest.mark.anyio
async def test_from_function(self):
"""Test creating a FunctionResource from a function."""
async def get_data() -> str: # pragma: no cover
"""get_data returns a string"""
return "Hello, world!"
resource = FunctionResource.from_function(
fn=get_data,
uri="function://test",
name="test",
)
assert resource.description == "get_data returns a string"
assert resource.mime_type == "text/plain"
assert resource.name == "test"
assert resource.uri == "function://test"
class TestFunctionResourceMetadata:
def test_from_function_with_metadata(self):
# from_function() accepts meta dict and stores it on the resource for static resources
def get_data() -> str: # pragma: no cover
return "test data"
metadata = {"cache_ttl": 300, "tags": ["data", "readonly"]}
resource = FunctionResource.from_function(
fn=get_data,
uri="resource://data",
meta=metadata,
)
assert resource.meta is not None
assert resource.meta == metadata
assert resource.meta["cache_ttl"] == 300
assert "data" in resource.meta["tags"]
assert "readonly" in resource.meta["tags"]
def test_from_function_without_metadata(self):
# meta parameter is optional and defaults to None for backward compatibility
def get_data() -> str: # pragma: no cover
return "test data"
resource = FunctionResource.from_function(
fn=get_data,
uri="resource://data",
)
assert resource.meta is None
@pytest.mark.anyio
async def test_sync_fn_runs_in_worker_thread():
"""Sync resource functions must run in a worker thread, not the event loop."""
main_thread = threading.get_ident()
fn_thread: list[int] = []
def blocking_fn() -> str:
fn_thread.append(threading.get_ident())
return "data"
resource = FunctionResource(uri="resource://test", name="test", fn=blocking_fn)
result = await resource.read()
assert result == "data"
assert fn_thread[0] != main_thread
@pytest.mark.anyio
async def test_sync_fn_does_not_block_event_loop():
"""A blocking sync resource function must not stall the event loop.
On regression (sync runs inline), anyio.from_thread.run_sync raises
RuntimeError because there is no worker-thread context, failing fast.
"""
handler_entered = anyio.Event()
release = threading.Event()
def blocking_fn() -> str:
anyio.from_thread.run_sync(handler_entered.set)
release.wait()
return "done"
resource = FunctionResource(uri="resource://test", name="test", fn=blocking_fn)
result: list[str | bytes] = []
async def run() -> None:
result.append(await resource.read())
with anyio.fail_after(5):
async with anyio.create_task_group() as tg:
tg.start_soon(run)
await handler_entered.wait()
release.set()
assert result == ["done"]
@pytest.mark.anyio
async def test_read_rejects_an_input_required_result_from_a_static_function():
"""A static resource function returning an InputRequiredResult is a mistake (it can
never read the retry's input_responses), so read() raises instead of JSON-dumping it."""
def ask() -> InputRequiredResult:
return InputRequiredResult(request_state="round-1")
resource = FunctionResource(uri="resource://ask", name="ask", fn=ask)
with pytest.raises(ValueError) as exc:
await resource.read()
assert str(exc.value) == snapshot(
"Error reading resource resource://ask: static resources cannot return "
"InputRequiredResult; only resource template functions participate in the multi-round-trip flow"
)