Achtung:
Problem: In PyCharm, when deciding a path in a py file, use os.getcwd() to get current working directory, it’s highly likely that cwd is not the directory where current file is in.
Why ?
Because “working directory” would be set inside Edit Configurations which would be shown if Run was executed, on the top.
A small issue can cost an hour.
Also, for a repo to function normally, the most important two things would be in File>Settings>Project>Project Intepreter and File>Settings>Tools>Python Integrated Tools for testing purpose.
pytest nowadays usually outperform unit test, like with usually beats classic open files.
Machine: Ubuntu 16.04; CentOS 7