feat(skills): standardize pytest-mock as Python mocking framework

[WilliamBerryiii]

Description

Standardized pytest-mock as the mocking framework for all Python skills, added an instructions document codifying the convention, and migrated the entire powerpoint skill test suite from unittest.mock.patch patterns to the mocker fixture. Also fixed per-skill virtual environment resolution in the PowerShell test and lint runners so they invoke pytest and ruff from each skill's .venv rather than relying on a global installation.

pytest-mock Standardization

The mocker fixture from pytest-mock provides automatic cleanup, reduces decorator nesting, and keeps mock setup visually close to the code under test — replacing @patch decorators and with patch() context managers that scattered setup away from assertions.

• Added python-tests.instructions.md (238 lines) to the coding-standards instructions, establishing mocker.patch() as the standard mocking mechanism with guidance on migration, mocker.AsyncMock(), mocker.patch.dict(), and prohibited patterns
• Migrated all 6 test files in the powerpoint skill from unittest.mock.patch to the mocker fixture
  • Converted @patch decorator chains, with patch(...) context managers, and @patch.dict calls to sequential mocker.patch() calls
  • Replaced AsyncMock imports with mocker.AsyncMock() in test_validate_slides.py
  • Decomposed parenthesized multi-context-manager blocks into individual mocker.patch() and mocker.patch.object() calls in test_render_pdf_images.py
  • MagicMock remains imported from unittest.mock where used as a standalone mock object, consistent with the instructions
• Added pytest-mock>=3.14 to pyproject.toml dev dependencies (resolved as 3.15.1 in uv.lock)

Per-Skill venv Resolution Fix

• Updated Invoke-PythonTests.ps1 and Invoke-PythonLint.ps1 to resolve pytest and ruff from each skill's .venv directory before falling back to global installations
  • Cascading resolution: .venv/bin/{tool} (Linux) → .venv/Scripts/{tool}.exe (Windows) → global → per-skill error
• Updated both Pester test files to match the new per-skill error reporting behavior

Collection and Plugin Updates

• Updated coding-standards and hve-core-all collection manifests to include the new python-tests.instructions.md entry
• Regenerated plugin READMEs and added symlinks for the new instructions file

Related Issue(s)

Closes #893

Type of Change

Select all that apply:

Code & Documentation:

• Bug fix (non-breaking change fixing an issue)
• New feature (non-breaking change adding functionality)
• Breaking change (fix or feature causing existing functionality to change)
• Documentation update

Infrastructure & Configuration:

• GitHub Actions workflow
• Linting configuration (markdown, PowerShell, etc.)
• Security configuration
• DevContainer configuration
• Dependency update

AI Artifacts:

• Reviewed contribution with prompt-builder agent and addressed all feedback
• Copilot instructions (.github/instructions/*.instructions.md)
• Copilot prompt (.github/prompts/*.prompt.md)
• Copilot agent (.github/agents/*.agent.md)
• Copilot skill (.github/skills/*/SKILL.md)

Note for AI Artifact Contributors:

• Agents: Research, indexing/referencing other project (using standard VS Code GitHub Copilot/MCP tools), planning, and general implementation agents likely already exist. Review .github/agents/ before creating new ones.
• Skills: Must include both bash and PowerShell scripts. See Skills.
• Model Versions: Only contributions targeting the latest Anthropic and OpenAI models will be accepted. Older model versions (e.g., GPT-3.5, Claude 3) will be rejected.
• See Agents Not Accepted and Model Version Requirements.

Other:

• Script/automation (.ps1, .sh, .py)
• Other (please describe):

Sample Prompts (for AI Artifact Contributions)

User Request:

"How should I mock dependencies in my Python tests?"

Execution Flow:

The python-tests.instructions.md file is attached automatically via its applyTo glob pattern when editing Python test files in skills. It provides inline guidance on using the mocker fixture from pytest-mock, including migration patterns from unittest.mock.

Output Artifacts:

No files created — the instructions file provides contextual guidance during test development.

Success Indicators:

New or modified Python tests use mocker.patch() instead of @patch decorators or with patch() context managers. MagicMock remains acceptable as a standalone mock object.

Testing

• All 626 pytest tests passing across the powerpoint skill test suite
• All 52 Pester tests passing for PowerShell scripts
• Coverage unchanged at 90.76%

Checklist

Required Checks

• Documentation is updated (if applicable)
• Files follow existing naming conventions
• Changes are backwards compatible (if applicable)
• Tests added for new functionality (if applicable)

AI Artifact Contributions

• Used /prompt-analyze to review contribution
• Addressed all feedback from prompt-builder review
• Verified contribution follows common standards and type-specific requirements

Required Automated Checks

The following validation commands must pass before merging:

• Markdown linting: npm run lint:md
• Spell checking: npm run spell-check
• Frontmatter validation: npm run lint:frontmatter
• Skill structure validation: npm run validate:skills
• Link validation: npm run lint:md-links
• PowerShell analysis: npm run lint:ps
• Plugin freshness: npm run plugin:generate

Security Considerations

• This PR does not contain any sensitive or NDA information
• Any new dependencies have been reviewed for security issues
• Security-related scripts follow the principle of least privilege

Additional Notes

• MagicMock remains imported from unittest.mock in test files where it creates standalone mock objects. The instructions document explicitly permits this pattern — only patch, patch.object, patch.dict, and AsyncMock are migrated to mocker equivalents.
• The venv resolution fix is a separate commit (5b5b314d) from the pytest-mock migration (82cd78d4) since it addresses a pre-existing bug discovered during testing.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 77.14286% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.05%. Comparing base (63d4c4d) to head (5e1d78b).
⚠️ Report is 11 commits behind head on main.

Files with missing lines	Patch %	Lines
scripts/linting/Invoke-PythonLint.ps1	76.47%	4 Missing ⚠️
scripts/linting/Invoke-PythonTests.ps1	77.77%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1170      +/-   ##
==========================================
- Coverage   87.68%   87.05%   -0.63%     
==========================================
  Files          61       59       -2     
  Lines        9239     8799     -440     
==========================================
- Hits         8101     7660     -441     
- Misses       1138     1139       +1     

Flag	Coverage Δ
pester	85.25% <77.14%> (-0.09%)	⬇️
pytest	91.53% <ø> (-1.05%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
scripts/linting/Invoke-PythonLint.ps1	84.50% <76.47%> (-3.63%)	⬇️
scripts/linting/Invoke-PythonTests.ps1	80.95% <77.77%> (-2.15%)	⬇️

... and 3 files with indirect coverage changes

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• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

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[katriendg]

Great addition!
There are two PRs that touch on Python based skills and will be affected by this PR. Question is should we merge them in first and then this, then add a backlog item to update the code from PRs #1128 and #978 - or merge the current one first and ask contributors to update based on the new requirements?

[WilliamBerryiii]

Great addition! There are two PRs that touch on Python based skills and will be affected by this PR. Question is should we merge them in first and then this, then add a backlog item to update the code from PRs #1128 and #978 - or merge the current one first and ask contributors to update based on the new requirements?

Great addition! There are two PRs that touch on Python based skills and will be affected by this PR. Question is should we merge them in first and then this, then add a backlog item to update the code from PRs #1128 and #978 - or merge the current one first and ask contributors to update based on the new requirements?

I'd like to merge the other PRs first so they are not blocked and then circle back to update these to match. There's also some type system work for python that I'd like to enforce, so I may do all that in one pass.

[nguyena2]

If this PR were a credit score, I’d rate it around 790/850.

Strong payment history: core changes are coherent and tests pass in the updated areas.
Low risk debt: only one known concern remains, and you explicitly marked it non-blocking.
Small utilization penalty: broad applyTo scope is a minor policy-quality issue, not a functional blocker.