style: align tests/ directory with Google Style Guide (#415)

[szy196]

Background & Motivation

This PR aligns the tests/ directory with the Google Style Guide and project-specific linting standards. It ensures that the test suite is maintainable, readable, and follows consistent patterns across all modules.

Proposed Changes

• Linting Configuration: Updated tests/.pylintrc to align with the root config (80-character limit, Google Style rules) while maintaining necessary pytest-specific overrides (redefined-outer-name, unused-argument).
• Module Documentation: Added module-level docstrings to all files in the tests/ directory.
• Sequence Comparisons: Refactored explicit empty list/dictionary comparisons to use implicit boolean checks (e.g., if not sequence:) as per the style guide.
• Line Length Management:
  • Manually wrapped long docstrings, comments, and strings where possible.
  • Added surgical # pylint: disable=line-too-long for 40 instances where wrapping was impractical (primarily long mock data strings).
• Test Fixes: Fixed tests/test_chromestatus.py which had incorrect mocks for network calls, causing flaky TimeoutError in some environments.
• formatting: Ran make lint-fix (pyink) to ensure consistent formatting across all modified files.
• pylint Rating: Achieved a 10.00/10 rating for the tests/ directory with the updated strict configuration.

Related Issues

Resolves #415
Follow-up issue created: #431 (to refactor test_phases.py into smaller modules).

Acceptance Criteria

• All test files pass pylint with the new configuration.
• make presubmit runs cleanly for the entire repository.
• All 393 tests pass with 93% coverage.

_{This PR description was drafted by Gemini}

[DanielRyanSmith]

One request, but otherwise this is almost ready. 🙂