Workaround py_test in bazel sandbox read only restriction

[gfrankliu]

The issue was also reported in bazel project over a year ago bazelbuild/bazel#21601 but I am wondering if there a way from rules_python side to workaround this limitation.

We are using huggingface-hub python package and py_test gives:

OSError: [Errno 30] Read-only file system: '/home/gfrankliu/.cache/huggingface'

huggingface-hub wants a writable cache directory and read-only would fail: huggingface/huggingface_hub#2797

[aignas]

Consider either patching the package to make the folder customizable (e.g. creating a temp folder for this) or other methods to work around this. The sandbox is read-only for a good reason to ensure that the processes are isolated.

Closing since this limitation in behaviour is not in rules_python.