The **fs‑fixture‑builder** package lets developers program‑matically define, create, and clean up temporary filesystem layouts for tests. By declaring files in memory and then writing or removing them in a temporary directory (with optional explicit‑resource‑management support), it simplifies testing of libraries or CLI tools that interact with the file system, and even includes a CLI to snapshot existing directories into reusable fixture code. It’s aimed at JavaScript/TypeScript test suites that need reliable, isolated file‑system fixtures.