test: add integration tests for full tunnel lifecycle

Exercises the complete PID file lifecycle end-to-end using a real subprocess
with a fake autossh (sleep 60 script), covering start, stop, status, stale PID
cleanup, restart, and idempotency scenarios.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/integration/test_lifecycle.py

@@ -0,0 +1,131 @@
+import os
+import signal
+import time
+import pytest
+from click.testing import CliRunner
+from autossh_mgr.cli import cli
+from autossh_mgr.config import save_tunnels, TunnelConfig, ensure_dirs
+from autossh_mgr.process import read_pid_file, is_process_alive
+
+
+@pytest.fixture
+def fake_autossh(tmp_path, monkeypatch):
+    """Replace autossh with a long-running dummy process."""
+    fake = tmp_path / "autossh"
+    fake.write_text("#!/bin/sh\nexec sleep 60\n")
+    fake.chmod(0o755)
+    monkeypatch.setenv("PATH", f"{tmp_path}:{os.environ['PATH']}")
+    return fake
+
+
+@pytest.fixture
+def config_dir(tmp_path):
+    ensure_dirs(tmp_path)
+    return tmp_path
+
+
+@pytest.fixture(autouse=True)
+def set_config_dir(config_dir, monkeypatch):
+    monkeypatch.setenv("AUTOSSH_MGR_CONFIG_DIR", str(config_dir))
+
+
+@pytest.fixture
+def tunnel(config_dir):
+    t = TunnelConfig(
+        name="test-tunnel",
+        host="relay.example.com",
+        user="deploy",
+        local_port=19999,
+        remote_port=29999,
+    )
+    save_tunnels(config_dir, [t])
+    return t
+
+
+@pytest.fixture
+def runner():
+    return CliRunner()
+
+
+def test_start_writes_pid_file(runner, config_dir, tunnel, fake_autossh):
+    result = runner.invoke(cli, ["start", "test-tunnel"])
+    assert result.exit_code == 0, result.output
+    pid_data = read_pid_file(config_dir, "test-tunnel")
+    assert pid_data is not None
+    pid, started_at = pid_data
+    assert is_process_alive(pid)
+    # cleanup
+    os.kill(pid, signal.SIGKILL)
+
+
+def test_stop_kills_process(runner, config_dir, tunnel, fake_autossh):
+    runner.invoke(cli, ["start", "test-tunnel"])
+    pid_data = read_pid_file(config_dir, "test-tunnel")
+    assert pid_data is not None
+    pid = pid_data[0]
+    assert is_process_alive(pid)
+
+    result = runner.invoke(cli, ["stop", "test-tunnel"])
+    assert result.exit_code == 0
+    time.sleep(0.2)
+    assert not is_process_alive(pid)
+    assert read_pid_file(config_dir, "test-tunnel") is None
+
+
+def test_status_shows_running(runner, config_dir, tunnel, fake_autossh):
+    runner.invoke(cli, ["start", "test-tunnel"])
+    result = runner.invoke(cli, ["status", "test-tunnel"])
+    assert result.exit_code == 0
+    assert "running" in result.output
+
+    pid_data = read_pid_file(config_dir, "test-tunnel")
+    if pid_data:
+        os.kill(pid_data[0], signal.SIGKILL)
+
+
+def test_stale_pid_cleaned_on_start(runner, config_dir, tunnel, fake_autossh):
+    from autossh_mgr.process import write_pid_file
+    from datetime import datetime, timezone
+    write_pid_file(config_dir, "test-tunnel", 9999999, datetime.now(timezone.utc))
+
+    result = runner.invoke(cli, ["start", "test-tunnel"])
+    assert result.exit_code == 0, result.output
+    assert "stale" in result.output.lower()
+
+    pid_data = read_pid_file(config_dir, "test-tunnel")
+    assert pid_data is not None
+    assert pid_data[0] != 9999999
+
+    os.kill(pid_data[0], signal.SIGKILL)
+
+
+def test_restart(runner, config_dir, tunnel, fake_autossh):
+    runner.invoke(cli, ["start", "test-tunnel"])
+    first_pid = read_pid_file(config_dir, "test-tunnel")[0]
+
+    result = runner.invoke(cli, ["restart", "test-tunnel"])
+    assert result.exit_code == 0, result.output
+
+    second_pid = read_pid_file(config_dir, "test-tunnel")[0]
+    assert second_pid != first_pid
+    assert is_process_alive(second_pid)
+
+    os.kill(second_pid, signal.SIGKILL)
+
+
+def test_idempotent_start(runner, config_dir, tunnel, fake_autossh):
+    runner.invoke(cli, ["start", "test-tunnel"])
+    first_pid = read_pid_file(config_dir, "test-tunnel")[0]
+
+    result = runner.invoke(cli, ["start", "test-tunnel"])
+    assert result.exit_code == 0
+    assert "already running" in result.output
+    assert read_pid_file(config_dir, "test-tunnel")[0] == first_pid
+
+    os.kill(first_pid, signal.SIGKILL)
+
+
+def test_idempotent_stop(runner, tunnel):
+    result = runner.invoke(cli, ["stop", "test-tunnel"])
+    assert result.exit_code == 0
+    assert "not running" in result.output