Crashing under a squashfuse_ll read-only mount

[hotpxl]

a detailed description of the bug or problem you are having

pytest is crashing with OSError: [Errno 38] Function not implemented when it's run under a squashfuse_ll mountpoint. the exception comes from within

_pytest/assertion/rewrite.py:1102: in try_makedirs
    os.makedirs(cache_dir, exist_ok=True)

this is because squashfuse_ll returns ENOSYS instead of EROFS for a read-only filesystem, which pytest doesn't know how to handle

pytest and operating system versions

d49f1fc (main as of Wed May 8 10:13:30 2024 -0300)