Parallel Test Execution in CI

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# PYTEST-XDIST: Parallel pytest execution
# pip install pytest-xdist
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# Run with N workers:
pytest tests/ -n 4         # 4 parallel workers (processes)
pytest tests/ -n auto      # Auto-detect CPU count

# With Allure:
pytest tests/api/ -n auto     --alluredir=allure-results     --dist=loadfile  # Keep tests from same file on same worker

# Distribution modes:
# -n auto --dist=load       # Default: distribute randomly across workers
# -n auto --dist=loadfile   # Tests from same file stay on same worker
# -n auto --dist=loadscope  # Tests with same scope stay on same worker

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# CRITICAL: MAKING TESTS PARALLEL-SAFE
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# ❌ TEST THAT BREAKS IN PARALLEL (shared mutable state):
def test_create_user_with_email_alice(api_session):
    # Problem: If two workers both create alice@test.com, second will get 409 Conflict
    response = api_session.post("/api/users", json={"email": "alice@test.com"})
    assert response.status_code == 201

# ✅ PARALLEL-SAFE VERSION (unique data per test):
import uuid
from datetime import datetime

def test_create_unique_user(api_session):
    # Each test run gets a unique email using UUID
    unique_email = f"test_{uuid.uuid4().hex[:8]}@parallel-test.com"
    response = api_session.post("/api/users", json={"email": unique_email})
    assert response.status_code == 201
    # Cleanup in fixture teardown

# ── PARALLEL-SAFE FIXTURES ────────────────────────────────────
import pytest
import uuid

@pytest.fixture(scope="function")
def unique_user(api_session):
    """Create a unique user per test — safe for parallel execution"""
    email = f"test_{uuid.uuid4().hex[:8]}@test.com"
    user = api_session.post("/api/users", json={
        "email": email,
        "password": "Test@1234",
        "name": "Test User"
    }).json()
    
    yield user
    
    # Cleanup: delete the user after test completes
    api_session.delete(f"/api/users/{user['id']}")

# ── PLAYWRIGHT PARALLEL EXECUTION ────────────────────────────
# playwright.config.ts
export default {
    fullyParallel: true,       // Each test file runs in parallel
    workers: process.env.CI ? 4 : undefined,  // 4 workers in CI, auto locally
    use: {
        baseURL: process.env.BASE_URL,
    },
    
    // Shard tests across multiple CI machines:
    // Run: npx playwright test --shard=1/4  (machine 1 of 4)
    //      npx playwright test --shard=2/4  (machine 2 of 4)
    //      npx playwright test --shard=3/4  (machine 3 of 4)
    //      npx playwright test --shard=4/4  (machine 4 of 4)
    // GitHub Actions matrix:
    // strategy:
    //   matrix:
    //     shard: [1, 2, 3, 4]
    // run: npx playwright test --shard=${{ matrix.shard }}/4
};