"gaudirun.py some/module.py:func" fails if "some/module.py" make use of "__file__" at load time

I was trying to write a GaudiConfig2 test in pytest using GaudiExeTest (!1605 (merged)), but this simple pattern does not work:

from GaudiTesting import GaudiExeTest

def config():
    pass

class Test(GaudiExeTest):
    command = ["gaudirun.py", f"{__file__}:config"]

fails because in !1301 (merged) I forgot to pass a meaningful __file__ value to the eval call.