run -m cannot find module (or package) in current directory
The directory from which
coverage was started should be added at the beginning of
sys.path (or perhaps even replace the first entry of
sys.path, which is the directory where
coverage is installed), so that
coverage run -m foo can find
foo in that directory (just as
python -m foo can find
foo in that directory).
Perhaps this modification should be made temporary though (e.g. by fooling around in execfile.py).