How to validate backup and restore processes for core-js polyfills?

Validating a backup of the core-js library involves ensuring that the archived files are complete, that restoration reproduces the exact module structure, and that every polyfill behaves identically to the original version. Yet it remains unclear how to automate integrity checks across the large set of individual polyfills, what level of test coverage is necessary to catch subtle behavioural differences, and how to isolate the restored library from the project’s existing dependencies during verification.

What automated test suite can confirm that each exported polyfill function matches the specification after a restore? How can checksums or metadata be used to detect corruption or truncation in the backup archive? In what ways can a temporary sandbox or module‑alias mechanism isolate the restored core-js to verify compatibility with the application code?