// tools/enforce-parallel-session-lock.test.mjs
// Stream H Task 7 — wrapper tests around the pure parallel-session-lock module.
import { describe, it, expect } from 'vitest';
import { decide } from './enforce-parallel-session-lock.mjs';

describe('enforce-parallel-session-lock wrapper (Stream H Task 7)', () => {
  it('allow when acquire succeeded (fresh own-lock)', () => {
    const r = decide({
      acquireResult: { acquired: true, holder: { session_id: 's1', pid: 100, acquired_at: 1000 } },
      sessionId: 's1',
    });
    expect(r.block).toBe(false);
  });

  it('block when another session holds the lock', () => {
    const r = decide({
      acquireResult: { acquired: false, holder: { session_id: 'other-session', pid: 999, acquired_at: 500 } },
      sessionId: 's1',
    });
    expect(r.block).toBe(true);
    expect(r.reason).toMatch(/parallel session lock.*other-session/i);
  });

  it('allow when same-session re-acquires (takeover)', () => {
    const r = decide({
      acquireResult: { acquired: true, holder: { session_id: 's1', pid: 100, acquired_at: 2000 } },
      sessionId: 's1',
    });
    expect(r.block).toBe(false);
  });

  it('fail-open when acquireResult is missing (internal error path)', () => {
    expect(decide({ acquireResult: null, sessionId: 's1' }).block).toBe(false);
    expect(decide({ acquireResult: undefined, sessionId: 's1' }).block).toBe(false);
  });

  it('block message identifies the other holder pid for human triage', () => {
    const r = decide({
      acquireResult: { acquired: false, holder: { session_id: 'other', pid: 42, acquired_at: 0 } },
      sessionId: 's1',
    });
    expect(r.reason).toMatch(/pid 42/);
  });
});