| name | Test Coverage |
| description | This skill should be used when the user asks to 'get to 100% coverage', 'improve test coverage', 'cover uncovered code', 'fix coverage gaps', or mentions uncovered lines or coverage percentage. Provides strategies for achieving complete test coverage through better code design. |
Getting to 100% Test Coverage
Philosophy
Coverage isn't about the number - it's about code quality. Code that's hard to test is usually hard to understand, maintain, and reason about. Pursuing 100% coverage forces you to write better code.
The Galahad Principle
Why 100% specifically? Because 100% provides disproportionate value compared to 95%:
Simplicity: A binary state (covered vs. not) provides clear, unambiguous signals. When everything is at 100%, any deviation immediately demands attention. "We have 100% coverage" is a statement you can trust. "We have 95% coverage" always raises the question: which 5% and why?
Trust: Complete coverage eliminates ambiguity. If coverage is always 100%, then any uncovered line is a bug - either in your code or your process. Absence of coverage becomes evidence of a problem, not just noise to filter out. You stop needing to ask "is this uncovered code intentional?" - the answer is always no.
Like Sir Galahad's pure heart granting him the strength of ten, 100% coverage gives you something that 95% coverage cannot: certainty.
Don't suppress coverage. Fix the code.
Workflow
- Find uncovered code with coverage reports
- For each gap, categorize why it's uncovered (see references/patterns.md)
- Apply the appropriate fix pattern
- Verify 100% coverage
Categorizing Coverage Gaps
For each uncovered section, ask: Why isn't this covered?
- Category A: Genuinely Unreachable Code - Make it an explicit error with
unreachable!()
