fix: resolve flaky test in CI by adding proper shutdown sequence

[Claude]

Summary

Fixed a flaky test that was causing intermittent CI failures. The test_stdio_initialize_and_tools_list test had a ~20-30% failure rate due to a race condition.

Problem

The test would fail with StopIteration when trying to retrieve the tools/list response (id=2). This happened because:

1. The test sent all input at once and closed stdin
2. The MCP server saw EOF on stdin and began shutting down
3. The server terminated before flushing the second response to stdout
4. The test only received the initialize response (id=1) but not the tools/list response (id=2)

Solution

Added a proper MCP shutdown sequence to the test:

• Send shutdown request (id=3)
• Send notifications/exit notification
• This ensures the server processes and flushes all pending responses before terminating

Also improved error messages to show which responses were actually received when assertions fail.

Testing

• Reproduced the issue locally (3 failures out of 15 runs = 20% failure rate)
• After fix: 90 consecutive test runs with 100% pass rate
• All tests in the suite pass
• Linter, formatter, and build all succeed

References

Fixes the test failure from: https://github.com/teh-hippo/tiny-ntfy-mcp/actions/runs/24599264157/job/71935021663

[Copilot]

Pull request overview

Resolves a flaky CI test by ensuring the MCP server receives an explicit shutdown sequence so it flushes pending responses before exiting.

Changes:

• Extend test_stdio_initialize_and_tools_list to send shutdown and notifications/exit after tools/list.
• Switch the test runner from subprocess.run(...) to subprocess.Popen(...).communicate(...) and improve assertion error messages.
• Update uv.lock to reflect tiny-ntfy-mcp version 2.0.9.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

File	Description
tests/test_mcp_server.py	Adds shutdown/exit messages, changes subprocess invocation, and improves missing-response diagnostics.
uv.lock	Updates locked editable package version to 2.0.9.

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[Copilot]

proc.communicate(..., timeout=5) can raise subprocess.TimeoutExpired; unlike subprocess.run(timeout=...), this won’t automatically terminate the child process. If the timeout is hit (e.g., CI slowdown), the test can leak a running MCP server process and potentially impact subsequent tests. Wrap communicate() in a try/except (kill/terminate + second communicate/wait in finally) or switch back to subprocess.run(..., timeout=...) now that the shutdown/exit sequence is included.

Suggested change

	stdout, stderr = proc.communicate(input=input_text, timeout=5)
	try:
	stdout, stderr = proc.communicate(input=input_text, timeout=5)
	except subprocess.TimeoutExpired:
	proc.kill()
	stdout, stderr = proc.communicate()
	pytest.fail(f"tiny_ntfy_mcp did not exit within timeout; stdout={stdout!r}, stderr={stderr!r}")
	finally:
	if proc.poll() is None:
	proc.kill()
	proc.wait()

[teh-hippo]

@anthropic-code-agent

[teh-hippo]

@openai-code-agent

[Copilot]

Pull request overview

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

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[Copilot]

This test now sends a shutdown request (id=3) but never asserts that the corresponding response was received. Adding an assertion for id=3 would ensure the graceful shutdown path actually ran (and would make failures easier to diagnose if shutdown handling regresses).

Suggested change

	assert 2 in responses_by_id, f"Missing tools/list response (id=2). Got responses: {[r.get('id') for r in responses]}"
	init_resp = responses_by_id[1]
	tools_resp = responses_by_id[2]
	assert init_resp["result"]["serverInfo"]["name"] == "tiny-ntfy-mcp"
	assert init_resp["result"]["serverInfo"]["version"]
	assert 2 in responses_by_id, f"Missing tools/list response (id=2). Got responses: {[r.get('id') for r in responses]}"
	assert 3 in responses_by_id, f"Missing shutdown response (id=3). Got responses: {[r.get('id') for r in responses]}"
	init_resp = responses_by_id[1]
	tools_resp = responses_by_id[2]
	shutdown_resp = responses_by_id[3]
	assert init_resp["result"]["serverInfo"]["name"] == "tiny-ntfy-mcp"
	assert init_resp["result"]["serverInfo"]["version"]
	assert "result" in shutdown_resp

[teh-hippo]

Superseded by #28, which uses a more robust approach that also addresses the mcp>=1.27.0 transport-close cancellation behaviour (see modelcontextprotocol/python-sdk#2334). The shutdown-handshake fix here still races the new cancel-on-stdin-close logic in the MCP server. The two outstanding review comments on this PR are not applicable to #28: the timeout-leak concern is handled there by an explicit kill+wait in a finally block, and the id=3 shutdown response no longer needs asserting because #28 doesn't send a shutdown request.