GPU index parameter gets ignored in `test.py`

[niqodea]

Hi, just a heads up about the script for someone experiencing similar problems. The current test.py script accepts gpu as argument but currently does not forward it to the other scripts. This, combined with the fact that env variables seem not to be forwarded when running the other scripts, is particularly insidious, as setting CUDA_VISIBLE_DEVICES won't work either (at least it didn't for me).