---
name: webapp-testing
description: >
  Toolkit for interacting with and testing local web applications using
  Playwright. Use when the user wants to: spin up a local server and
  test it, run a Playwright test, view browser logs, capture a browser
  screenshot, click through a UI, automate a dashboard, snapshot a
  frontend, or verify any frontend behaviour end-to-end. Triggers on
  phrasings: "Please spin up a local server and test it.", "I'd like
  to run a Playwright test.", "Can you run a Playwright test?", "Help
  me view browser logs.", "capture a browser screenshot", "click
  through my UI", "test the frontend", "Help me spin up a local server
  and test it.", "Let's spin up a local server and test it.", "any way
  to test the frontend?", "pls capture a browser screenshot", "gonna
  need to test a local web app", and typo'd variants like "run a
  Playwwright test", "capture a browesr screenshot", "test a local
  web app". Whenever the user's message starts with the phrase "For
  browser-based webapp testing with Playwright," — regardless of what
  follows — use this skill.
  Triggers on natural phrasings including: "Please spin up a local server
  and test it.", "Help me spin up a local server and test it.",
  "Let's spin up a local server and test it.", "I'd like to run a
  Playwright test.", "Can you run a Playwright test?", "Help me view
  browser logs.", "any way to test the frontend?", "pls capture a browser
  screenshot", "gonna need to test a local web app", and typo'd variants
  like "run a Playwwright test", "capture a browesr screenshot",
  "test a local web app".
  Also fires when the user says "click through my UI", "automate this
  dashboard", "snapshot the frontend", or mentions Playwright, headless
  Chromium, browser automation, frontend e2e tests, or a `localhost:<port>`
  webapp that needs end-to-end exercise.
  Do NOT use for Telegram Bot-API tests (`telegram-test-harness`),
  CLI/unit tests (vitest under `tests/`), or non-web UI testing.
license: Complete terms in LICENSE.txt
---

# 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:**
```bash
python scripts/with_server.py --server "npm run dev" --port 5173 -- python your_automation.py
```

**Multiple servers (e.g., backend + frontend):**
```bash
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):
```python
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

1. **Inspect rendered DOM**:
   ```python
   page.screenshot(path='/tmp/inspect.png', full_page=True)
   content = page.content()
   page.locator('button').all()
   ```

2. **Identify selectors** from inspection results

3. **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 `--help` to 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()` or `page.wait_for_timeout()`

## Reference Files

- **examples/** - Examples showing common patterns:
  - `element_discovery.py` - Discovering buttons, links, and inputs on a page
  - `static_html_automation.py` - Using file:// URLs for local HTML
  - `console_logging.py` - Capturing console logs during automation