pytest-sigil

Proper fixture resource cleanup by handling signals

A pytest plugin that ensures your test fixtures clean up properly when receiving termination signals (SIGTERM), preventing resource leaks and ensuring graceful shutdowns.

Problem

When pytest receives a SIGTERM signal (e.g., from cancelled CI/CD jobs), it terminates immediately without running fixture teardown code. This can leave resources dangling:

• Database connections remain open
• Temporary files aren't cleaned up
• Docker containers keep running
• File locks persist

Related: See pytest issues #5243 & #9142 for discussion on this behavior.

Solution

pytest-sigil intercepts SIGTERM signals and reroutes them to SIGINT handlers, allowing pytest to:

1. Execute fixture teardown code
2. Run cleanup callbacks
3. Exit gracefully with proper status codes

Installation

pip install pytest-sigil

Usage

The plugin activates automatically once installed—no configuration needed.

import pytest


@pytest.fixture
def database_connection():
    conn = create_connection()
    yield conn
    conn.close()  # ✓ Now runs even on SIGTERM

Disable the Plugin

If needed, disable it for specific test runs:

pytest -p no:sigil

CI/CD Configuration

⚠️ Important: Requires proper signal forwarding in containerized environments. Without an init process, SIGTERM won't reach pytest.

GitLab CI

variables:
  FF_USE_INIT_WITH_DOCKER_EXECUTOR: "true"

This flag ensures GitLab's Docker executor uses an init process (tini) that properly forwards SIGTERM to pytest. See GitLab's feature flag documentation for details.

Note: Without proper signal forwarding, the plugin cannot intercept SIGTERM. Check your CI provider's documentation for signal handling behavior.

How It Works

# On session start: SIGTERM → SIGINT
signal.signal(signal.SIGTERM, signal.getsignal(signal.SIGINT))

# On session finish: Restore original SIGTERM handler
signal.signal(signal.SIGTERM, original_handler)

This simple rerouting leverages pytest's existing interrupt handling, ensuring all cleanup hooks execute properly.

License

MIT © lovetheguitar