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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.

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Decision Tree: Choosing Your Approach

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Example: Using with_server.py

To start a server, run --help first, then use the helper: Single server:
Multiple servers (e.g., backend + frontend):
To create an automation script, include only Playwright logic (servers are managed automatically):

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Reconnaissance-Then-Action Pattern

  1. Inspect rendered DOM:
  2. Identify selectors from inspection results
  3. Execute actions using discovered selectors

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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

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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()

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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