webapp-testing
[IMPORTANT] Use
TaskCreateto break ALL work into small tasks BEFORE starting — including tasks for each file read. This prevents context loss from long files. For simple tasks, AI MUST ask user whether to skip.
Prerequisites: MUST READ .claude/skills/shared/evidence-based-reasoning-protocol.md before executing.
Quick Summary
Goal: Test local web applications using Python Playwright scripts with server lifecycle management.
For full-site QA audits (accessibility, performance, security, SEO), use
test-uiinstead.
Workflow:
- Decide Approach — Static HTML (read selectors directly) vs dynamic app (use server helper)
- Start Server — Use
scripts/with_server.pyfor automatic server lifecycle management - Reconnaissance — Navigate, wait for
networkidle, screenshot/inspect DOM - Execute Actions — Write Playwright scripts using discovered selectors
Key Rules:
- Always wait for
networkidlebefore inspecting DOM on dynamic apps - Use bundled scripts as black boxes; run
--helpfirst, don't read source - Always launch Chromium in headless mode and close browser when done
Be skeptical. Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence percentages (Idea should be more than 80%).
Web Application Testing
To test local web applications, write native Python Playwright scripts.
Helper Scripts Available:
scripts/with_server.py- Manages server lifecycle (supports multiple servers)
Always run scripts with --help first to see usage. DO NOT read the source until you try running the script first and find that a customized solution is abslutely necessary. These scripts can be very large and thus pollute your context window. They exist to be called directly as black-box scripts rather than ingested into your context window.
Decision Tree: Choosing Your Approach
User task → Is it static HTML?
├─ Yes → Read HTML file directly to identify selectors
│ ├─ Success → Write Playwright script using selectors
│ └─ Fails/Incomplete → Treat as dynamic (below)
│
└─ No (dynamic webapp) → Is the server already running?
├─ No → Run: python scripts/with_server.py --help
│ Then use the helper + write simplified Playwright script
│
└─ Yes → Reconnaissance-then-action:
1. Navigate and wait for networkidle
2. Take screenshot or inspect DOM
3. Identify selectors from rendered state
4. Execute actions with discovered selectors
Example: Using with_server.py
To start a server, run --help first, then use the helper:
Single server:
python scripts/with_server.py --server "npm run dev" --port 5173 -- python your_automation.py
Multiple servers (e.g., backend + frontend):
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
To create an automation script, include only Playwright logic (servers are managed automatically):
from playwright.sync_api import sync_playwright
with sync_playwright() as p:
browser = p.chromium.launch(headless=True) # Always launch chromium in headless mode
page = browser.new_page()
page.goto('http://localhost:5173') # Server already running and ready
page.wait_for_load_state('networkidle') # CRITICAL: Wait for JS to execute
# ... your automation logic
browser.close()
Reconnaissance-Then-Action Pattern
-
Inspect rendered DOM:
page.screenshot(path='/tmp/inspect.png', full_page=True) content = page.content() page.locator('button').all() -
Identify selectors from inspection results
-
Execute actions using discovered selectors
Common Pitfall
❌ Don't inspect the DOM before waiting for networkidle on dynamic apps
✅ Do wait for page.wait_for_load_state('networkidle') before inspection
Best Practices
- Use bundled scripts as black boxes - To accomplish a task, consider whether one of the scripts available in
scripts/can help. These scripts handle common, complex workflows reliably without cluttering the context window. Use--helpto see usage, then invoke directly. - Use
sync_playwright()for synchronous scripts - Always close the browser when done
- Use descriptive selectors:
text=,role=, CSS selectors, or IDs - Add appropriate waits:
page.wait_for_selector()orpage.wait_for_timeout()
Reference Files
- examples/ - Examples showing common patterns:
element_discovery.py- Discovering buttons, links, and inputs on a pagestatic_html_automation.py- Using file:// URLs for local HTMLconsole_logging.py- Capturing console logs during automation
IMPORTANT Task Planning Notes (MUST FOLLOW)
- Always plan and break work into many small todo tasks
- Always add a final review todo task to verify work quality and identify fixes/enhancements