Webapp Testing

Web Application Testing

Test local web applications using native Python Playwright scripts.

Helper Scripts

• scripts/with_server.py - Manages server lifecycle (supports multiple servers)

Always run with --help first to see usage.

Decision Tree

User task → Is it static HTML?
    ├─ Yes → Read HTML file directly for selectors
    │         → Write Playwright script
    │
    └─ No (dynamic webapp) → Is server running?
        ├─ No → Use with_server.py helper
        │
        └─ Yes → Reconnaissance-then-action:
            1. Navigate and wait for networkidle
            2. Take screenshot or inspect DOM
            3. Identify selectors
            4. Execute actions

Using with_server.py

Single server:

python scripts/with_server.py --server "npm run dev" --port 5173 -- python your_automation.py

Multiple servers:

python scripts/with_server.py \
  --server "cd backend && python server.py" --port 3000 \
  --server "cd frontend && npm run dev" --port 5173 \
  -- python your_automation.py

Playwright Script Template

from playwright.sync_api import sync_playwright

with sync_playwright() as p:
    browser = p.chromium.launch(headless=True)
    page = browser.new_page()
    page.goto('http://localhost:5173')
    page.wait_for_load_state('networkidle')  # CRITICAL!

    # Reconnaissance
    page.screenshot(path='/tmp/inspect.png', full_page=True)

    # Actions
    page.locator('button:has-text("Submit")').click()

    browser.close()

Common Pitfall

Don't inspect DOM before networkidle on dynamic apps. Do wait for page.wait_for_load_state('networkidle') first.

Best Practices

• Use sync_playwright() for synchronous scripts
• Always close the browser when done
• Use descriptive selectors: text=, role=, CSS, IDs
• Add appropriate waits: wait_for_selector(), wait_for_timeout()