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odysseus/tests/test_mcp_cache_invalidation.py
T

103 lines
3.7 KiB
Python

"""Regression test: McpManager._generation must bust the tool prompt cache
when a server connects/disconnects with the same tool count.
Before the fix, cache_key was (disabled_map, len(_tools)). A reconnect that
preserved the tool count left the stale description in place. After the fix
the _generation counter is included so any structural change invalidates it.
"""
import asyncio
from src.mcp_manager import McpManager
def _make_mgr():
return McpManager()
def _inject_tools(mgr, server_id: str, tools: list):
"""Directly populate internal dicts as _connect_stdio would after success."""
mgr._tools[server_id] = tools
mgr._connections[server_id] = {"status": "connected", "name": server_id}
# ---------------------------------------------------------------------------
# _generation increments on disconnect
# ---------------------------------------------------------------------------
def test_generation_increments_on_disconnect():
mgr = _make_mgr()
assert mgr._generation == 0
_inject_tools(mgr, "srv1", [{"name": "tool_a"}])
mgr._generation += 1 # simulate connect increment
gen_before = mgr._generation
asyncio.run(mgr.disconnect_server("srv1"))
assert mgr._generation == gen_before + 1
# ---------------------------------------------------------------------------
# Core cache-invalidation regression: stale description after reconnect
# ---------------------------------------------------------------------------
def test_prompt_cache_busted_after_disconnect_same_tool_count():
"""The stale-cache bug: two different servers each have 1 tool.
After the first disconnects and the second connects, the cache must
reflect the new server's tools, not the old one's description.
"""
mgr = _make_mgr()
# Connect server A with one tool
_inject_tools(mgr, "srv_a", [{"name": "tool_alpha", "description": "Alpha tool",
"inputSchema": {"type": "object", "properties": {}}}])
mgr._generation += 1 # simulated successful connect
desc_a = mgr.get_tool_descriptions_for_prompt()
assert "tool_alpha" in desc_a
# Disconnect A — same tool count (1) as what follows
asyncio.run(mgr.disconnect_server("srv_a")) # bumps _generation
# Connect server B with a *different* tool but same count (1)
_inject_tools(mgr, "srv_b", [{"name": "tool_beta", "description": "Beta tool",
"inputSchema": {"type": "object", "properties": {}}}])
mgr._generation += 1 # simulated successful connect
desc_b = mgr.get_tool_descriptions_for_prompt()
# Without the fix both describe tool_alpha (stale cache hit).
assert "tool_beta" in desc_b, (
"Cache was not invalidated: got stale description after reconnect"
)
assert "tool_alpha" not in desc_b
def test_owned_stdio_stack_closes_in_connection_owner_task():
"""MCP cancel scopes must be exited by the task that entered them."""
class Stack:
def __init__(self):
self.owner = None
self.closed_in = None
async def aclose(self):
self.closed_in = asyncio.current_task()
assert self.closed_in is self.owner
async def run():
mgr = McpManager()
stack = Stack()
async def owner():
stack.owner = asyncio.current_task()
mgr._stacks["owned"] = stack
await mgr.hold_owned_connection("owned")
owner_task = asyncio.create_task(owner())
await asyncio.sleep(0)
await mgr.disconnect_server("owned")
assert owner_task.done()
assert stack.closed_in is owner_task
assert "owned" not in mgr._stacks
asyncio.run(run())