Running coverage on a non-existent file gives a meaningful error message, and then signs off with an unexpected exception report.
I hope the following test case says it all:
coverage run a_file_that_does_not_exist No file to run: 'a_file_that_does_not_exist' Exception AttributeError: "'NoneType' object has no attribute 'isabs'" in <function _remove at 0x026E23F0> ignored
ver Microsoft Windows [Version 6.0.6002]
python --version Python 2.7.1
coverage --version Coverage.py, version 3.5.1. http://nedbatchelder.com/code/coverage }}}
Obviously, this isn't a big problem, but worth noting.