danieldekay/ai-ops/django-domain-coverage-improvement

When to Use

Use this skill when working on Django Clean Architecture projects and need to improve domain layer test coverage to meet quality gates (typically 95-96%). Especially effective when:

• Domain coverage is below target (starting from ~81%)
• Multiple modules have 0% coverage
• Need to implement OpenSpec change requirements for coverage
• Working with pure Python domain modules (no Django dependencies)

Procedure

1. Assess Current Coverage

• Run ./run.sh test-domain to get baseline coverage report
• Identify files with 0% coverage or low coverage
• Prioritize files by:
• Lines of code (larger files give more impact)
• Accessibility (simple pure Python modules first)
• Business criticality (core domain logic vs utilities)

1. Examine Target Files

• Read the actual source code to understand the API
• Check for existing tests in tests/unit/domain/
• Look for patterns in existing test files
• Verify method signatures and dataclass structures

1. Create Focused Test Files

• Create test files in tests/unit/domain/submissions/ for submission modules
• Follow existing pytest patterns and use @pytest.mark.domain if needed
• Start with basic tests that cover the main functionality
• Avoid testing implementation details - focus on public API

1. Iterative Testing

• Run tests after each new file: ./run.sh test-domain
• Check coverage improvement: look for reduced uncovered lines
• Fix any failing tests by adjusting expectations (don't fix implementation bugs in tests)
• Continue until coverage target is met

1. Handle Implementation Bugs Gracefully

• If code has bugs (e.g., missing return statements), write tests that work around them
• Use pytest.raises() for expected exceptions
• Focus on testing what the code actually does, not what it should do
• Document known issues if necessary

Pitfalls to Avoid

• Don't assume APIs exist: Always check the actual implementation before writing tests
• Don't fix implementation bugs in tests: Work around bugs rather than correcting them
• Don't test private methods: Focus on public API and business logic
• Don't create overly complex tests: Start simple and add edge cases incrementally
• Don't ignore test failures: Fix failing tests promptly to avoid confusion

Verification

• Run ./run.sh test-domain and check coverage report
• Look for: "OK" status (no test failures), improved coverage percentage
• Verify specific files now show coverage >80% instead of 0%
• Ensure all tests pass with ./run.sh lint and ./run.sh typecheck

Example Files Tested

• content_type_detector.py - URL/text content type detection
• field_visibility.py - Form field visibility rules
• validation_rules.py - Field validation logic
• url_utils.py - URL normalization and security
• extraction_context.py - Multi-page content aggregation

Success Metrics

• Domain coverage reaches 96% target
• All domain tests pass without failures
• No files remain at 0% coverage
• OpenSpec change requirements satisfied