Write Unit Tests for Shell Scripts

This is a skill for writing comprehensive unit tests for shell scripts using Bats (Bash Automated Testing System), covering test patterns, fixtures, and best practices for production-grade shell testing. Its workflow: confirm which shell dialects and environments the scripts must run under, set up a test structure with helpers and fixtures, write tests that assert exit codes, output, and side effects rather than just that a script runs without error, and add setup and teardown so tests run cleanly in CI. Detailed patterns and examples live in a companion resources/implementation-playbook.md file.

Use this skill when writing unit tests for shell scripts, implementing TDD for scripts, setting up automated shell testing in CI/CD, testing edge cases and error conditions, or validating behavior across shell environments. Don't use it if the project doesn't use shell scripts, if you need integration tests that go beyond shell behavior, or if the goal is only linting or formatting rather than behavioral testing.

Input is a shell script and its target dialects and environments; output is a Bats test suite - structured with helpers, fixtures, and setup/teardown - asserting exit codes, output content, and side effects, wired into CI/CD, with detailed test patterns available in the companion playbook file.

Developers writing or maintaining shell scripts who need production-grade, CI-integrated unit tests covering exit codes, output, and error conditions, rather than relying on manual testing or linting alone.