File Upload & Download

The upload control is a native <input type="file"> — the OS file picker it opens is outside the browser's DOM, so most tools need a "set input files" style API rather than a click-driven flow.

The download link generates its file client-side with no server round-trip, so there's no network request to wait on — only a completed download to verify. Both the filename and the file's contents carry a timestamp that's different on every click, so a test that hardcodes the exact filename will only pass once — the status line below echoes what was actually generated, since most tools can't inspect the OS downloads folder directly.