Test-Driven Development

Load the language standards skill first

Before writing the first test, load the standards skill for the language you are about to write. This skill owns the loop; the language skill owns the code. Loading this one does not satisfy the other, and being mid-task is not a reason to skip it.

Philosophy

Examples in this skill use TypeScript. The principles are language-agnostic. For Go, test style (assertions, tables, doubles, helpers) comes from go-idiomatic § Testing, not from these examples.

Core principle: Tests should verify behavior through public interfaces, not implementation details. Code can change entirely; tests shouldn't.