Enhance setup and testing scripts for improved package management and logging

- Updated setup.sh to check for Nala installation and provide alternative installation methods based on Ubuntu version.
- Added error handling for package installation, allowing fallback to apt if Nala fails.
- Introduced startup.sh to perform container startup checks, including system info and permissions for logs directory.
- Created test-setup.sh to validate bootstrap and setup scripts, including detailed logging of package availability and installation results.
- Implemented checks for missing packages and provided recommendations for manual installation.
- Enhanced logging for better traceability of actions and errors during setup and testing processes.

dotfiles/README.md

@@ -93,6 +93,41 @@ curl -fsSL https://raw.githubusercontent.com/acedanger/shell/main/bootstrap.sh |
    - Configure zoxide for better navigation
    - Install and configure Git
 
+## Testing
+
+The repository includes a comprehensive testing framework to validate the shell setup process across different environments.
+
+### Docker-Based Testing
+
+Tests are run in isolated Docker containers to ensure consistent, repeatable validation:
+- **Ubuntu 24.04 environment**: Tests compatibility with the latest Ubuntu LTS
+- **Debian 12 environment**: Tests compatibility with Debian Stable
+
+### Test Coverage
+
+The tests validate:
+- Package availability in repositories
+- Successful installation of all packages in `packages.list`
+- Oh My Zsh installation
+- Zsh plugin installation
+- Dotfile symlinking
+- NVM and Node.js setup
+
+### Running Tests
+
+```bash
+# Test your setup on Ubuntu
+./run-docker-tests.sh ubuntu
+
+# Test your setup on Debian
+./run-docker-tests.sh debian
+
+# Run a full bootstrap test (including installation)
+./run-docker-tests.sh full-ubuntu
+```
+
+For more details on testing, see [Testing Documentation](../docs/testing.md).
+
 ## Manual Steps
 
 If you need to manually set up aliases: