name: webapp_testing
router_kit: FullStackKit
description: Toolkit for interacting with and testing local web applications using Playwright. Supports verifying frontend functionality, debugging UI behavior, capturing browser screenshots, and viewing browser logs.
license: Complete terms in LICENSE.txt
metadata:
skillport:
category: auto-healed
tags: [accessibility, api integration, backend, browser, browser apis, client-side, components, css3, cypress, debugging, deployment, e2e, frameworks, frontend, fullstack, html5, integration, javascript, libraries, node.js, npm, performance optimization, playwright, responsive design, seo, state management, testing, typescript, ui/ux, web development, webapp testing]

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

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

🔄 Workflow

Source: Playwright Python Documentation & Testing Hybrid Web Apps (2025)

Phase 1: Environment & Reconnaissance

• [ ] Server Management: Automatically start test environment (Frontend/Backend) using scripts/with_server.py --server "...".
• [ ] DOM Inspection: Perform selector analysis with page.content() and screenshot after reaching networkidle state.
• [ ] Selector Strategy: Determine role, text or test-id based selectors for stable tests.

Phase 2: Scripting & Automation

• [ ] Action Chain: Code click, form filling and navigation steps using Playwright API.
• [ ] Assertion Logic: Check page title, element visibility or URL correctness with expect() methods.
• [ ] Visual Testing: Perform Snapshot comparisons (screenshot audit) for interface consistency.

Phase 3: Debug & Reporting

• [ ] Log Audit: Audit browser console outputs (Console logs) and network errors (Failed requests).
• [ ] Trace Analysis: Perform step-by-step debugging using Playwright Trace Viewer for failed tests.
• [ ] CI/CD Alignment: Verify that tests run smoothly in headless mode and continuous integration pipeline.

Checkpoints

Webapp Testing v2.0 - With Workflow