Real file from a public repo · synced Sep 3, 2026
writing-unit-tests
Use when writing or refactoring unit tests - a new test file, added cases, a flaky test, an unreadable one. Encodes behavior-first testing: one behavior per test, names that state the claim, deterministic setup, mocks only at boundaries you do not own. Use whenever a test is being written, even a quick one, and whenever a test needs a sleep, a mock of your own code, or a copy of the implementation's math.
Works with
Install in three steps
- 1
Download the ZIP
One file per agent, plus INSTALL.md with the exact paths below.
- 2
Claude Code: copy SKILL.md into your skills folder
.claude/skills/writing-unit-tests/SKILL.md # this project ~/.claude/skills/writing-unit-tests/SKILL.md # every project
- 3
Other agents: use the matching file
skill.mdc goes in Cursor’s .cursor/rules/. AGENTS.md works as GitHub Copilot instructions, a legacy .cursorrules, or a Codex / Gemini CLI instructions file.

