What problem does it solve? New or modified source files often ship without tests, leaving error paths, boundary conditions, and confirmation-gated destructive actions unexercised — the exact lines that break in production. This Skill ensures every .ts/.tsx/.rs file you create or modify gets a co-located test driving its own coverage to at least 95% on lines, branches, functions, and statements. ## Core Features & Use Cases - Per-file coverage checks: Scoped scripts report exact uncovered line numbers, branches, and functions for only the files you touched, avoiding slow and noisy repo-wide runs. - Edge-case guidance: A checklist helps you pick which categories genuinely apply — empty inputs, error paths, destructive-action confirmations, async states — instead of padding coverage with hollow tests. - Repo-specific gotcha references: Documents known Vitest/jsdom quirks (query-cache bleed, missing PointerEvent, Monaco fakes) and Rust test conventions (tempdir git2 repos, --lib scoping, nightly branch coverage). - Use Case: After adding a new React hook or a Rust service function, run the coverage script on that file, see it reports 82% with uncovered lines 45-52, add tests targeting those branches, and rerun until all metrics pass 95%. ## Quick Start Ask the AI to add a feature or fix a bug in a source file and require that the changed files reach 95% test coverage with real edge-case tests before finishing.
