Both mock.module and spyOn cause cross-file test pollution in Bun's
single-process runner — mock.module poisons the module registry permanently,
and spyOn doesn't correctly restore ESM live bindings across files on Linux.
The real downloadCommentImages is safe to call because test comment bodies
contain no GitHub image URLs, so the function finds zero images and returns
an empty Map naturally. The only side effect is mkdir("/tmp/github-images")
which is harmless on CI runners.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>