uno-test-resize-app-window

name	uno-test-resize-app-window
description	Resize a running Uno Platform desktop app window on macOS for visual testing. Use when you need to verify responsive layout reflow, test breakpoints, or validate UI at different window sizes. Requires macOS Accessibility API access.
metadata	{"author":"https://github.com/VincentH-Net","version":"1.1","category":"testing","platform":"macOS"}

Resize App Window on macOS for Visual Testing

Resize a running Uno Platform desktop app window programmatically using the macOS Accessibility API. Useful for verifying responsive layout behavior at specific widths without manual interaction.

Prerequisites

• macOS with Accessibility API access granted to the terminal/IDE
• A running Uno Platform desktop app (use uno_app_start / uno_app_get_runtime_info first)

Usage

Run resize-window.sh with three arguments:

resize-window.sh APP_NAME WIDTH HEIGHT

• APP_NAME — the app's process name (from uno_app_get_runtime_info → Process Name)
• WIDTH — target window width in pixels
• HEIGHT — target window height in pixels

Common Test Widths

Width	Columns (typical)	Use case
500	1	Mobile / narrow
750	2	Tablet / medium
1024	3	Desktop / wide
1280	3-4	Large desktop

Workflow

1. Start the app with uno_app_start
2. Confirm running with uno_app_get_runtime_info (note Process Name)
3. Take initial screenshot with uno_app_get_screenshot
4. Run resize-window.sh "AppName" 500 800
5. Take screenshot and verify layout reflow
6. Repeat at additional widths as needed
7. Restore original size when done

Troubleshooting

• "App not found": Verify the process name matches exactly (case-sensitive). Check with uno_app_get_runtime_info.
• "Resize failed: -25211": Accessibility access not granted. The user must grant access in System Settings > Privacy & Security > Accessibility for the terminal app.
• Xcode objc warnings in stderr: Harmless; ignore. The resize still succeeds.

Notes

• This technique uses the macOS Accessibility API (AXUIElement), not AppleScript. AppleScript System Events requires separate assistive access and often fails for non-scriptable apps.
• The script targets the first window of the process. If the app has multiple windows, only the first is resized.
• Window position can also be set by replacing kAXSizeAttribute with kAXPositionAttribute and using CGPoint instead of CGSize.