evilissimo/software-design
Use before implementing or refactoring software. Contains two skills: (1) Modular Software Design — for designing module boundaries, APIs, layers, abstractions, services, repositories, adapters, or architecture, helping reduce total system complexity by creating deep modules, hiding implementation knowledge, avoiding leakage and pass-through APIs, comparing alternative designs, documenting interfaces before coding, and critiquing existing architecture; and (2) Software Testing — for writing unit tests, integration tests, or end-to-end tests, creating mocks/stubs/fakes, designing a testing strategy, doing TDD, reviewing test quality, fixing flaky tests, or refactoring test suites, generating risk-focused test plans, picking appropriate test levels, choosing between mocks/fakes/real dependencies, and applying Arrange-Act-Assert patterns with concrete examples.
93
94%
Does it follow best practices?
Impact
92%
1.12xAverage score across 5 eval scenarios
Passed
No known issues
coverage-criteria.mdskills/software-testing/references/
Coverage Criteria
Coverage is feedback, not the goal. It reveals blind spots but does not prove tests are meaningful.
Common Criteria
- Statement coverage: lines executed. Useful for finding dead zones, weak as a confidence metric.
- Branch coverage: both sides of decisions. Good for business rules and error paths.
- Condition coverage: boolean subexpressions vary independently. Useful for complex guards.
- Path coverage: combinations of branches. Usually explodes quickly; use selectively.
- Input-space coverage: representatives from valid, invalid, boundary, and semantic categories.
- Mutation coverage: checks whether plausible small code changes are killed by tests.
How to Use
Ask: what behavior did we forget? Continue when coverage reveals meaningful untested decisions, error handling, null/empty handling, loops, thresholds, or mutations that would survive. Stop when uncovered code is trivial, unreachable, duplicated by a stronger test, or low risk.