Add comprehensive test suite with GitHub Actions CI/CD integration

[Copilot]

Implements a complete test infrastructure with 14 unit tests achieving 100% coverage on main.py, integrated with GitHub Actions for automated cross-platform testing.

Test Suite

• Coverage: All functions in main.py (openLicense, openEULA, ProgramVer, get_resource_path)
• Mocking strategy: Uses unittest.mock to test GUI components without requiring display
• Test organization: 4 test classes covering unit and integration scenarios

Code Improvements

• Added get_resource_path() helper for absolute file path resolution
• Replaced hardcoded relative paths with dynamic absolute paths
• Removed redundant file.close() calls (already handled by context manager)

# Before
with open("LICENSE.txt", "r", encoding="UTF-8") as licensefile:
    licensecontents = licensefile.read()
licensefile.close()  # Redundant

# After
license_path = get_resource_path("LICENSE.txt")
with open(license_path, "r", encoding="UTF-8") as licensefile:
    licensecontents = licensefile.read()

CI/CD Integration

• Platforms: Ubuntu, Windows, macOS
• Python versions: 3.9, 3.10, 3.11, 3.12
• Features: Headless GUI testing (xvfb), coverage reporting to Codecov

Configuration

• pytest.ini: Test discovery and execution settings
• requirements.txt: Added pytest>=7.4.0, pytest-cov>=4.1.0
• .github/workflows/tests.yml: Multi-platform test matrix with conditional requirements installation

Documentation

• tests/README.md: Complete guide for running tests locally and in CI
• Main README: Testing section with badge and usage examples

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Create a comprehensive test suite with a GitHub Actions integration

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[github-actions]

Thank you for your contribution, please read and sign our CLA. Instructions on how to do so can be found in the CONTRIBUTING.md document.

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I have read the CLA Document, and I hereby sign the CLA.

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