Why does running "setup.py test" run my console script?

Question

My very simple example project contains:

addtest/
  setup.py
  addtest/
    __init__.py
    __main__.py
    app.py

My app.py is just:

def main():
    raise SystemExit("Command line entry point called.")

My __main__.py is just:

from addtest.app import main
main()

My setup.py contains:

from setuptools import setup, find_packages

setup(
    name='AddTest',
    version='1.0',
    packages=find_packages(),

    entry_points={
        'console_scripts': ['addtest = addtest.app:main']
    },
)

I would expect that running python setup.py test would do nothing, since no unit tests are written. However, running it in a clean virtualenv (Python 3.6.6 on Ubuntu 18.04.1) gives me:

$ python setup.py test
running test
running egg_info
writing AddTest.egg-info/PKG-INFO
writing dependency_links to AddTest.egg-info/dependency_links.txt
writing entry points to AddTest.egg-info/entry_points.txt
writing top-level names to AddTest.egg-info/top_level.txt
reading manifest file 'AddTest.egg-info/SOURCES.txt'
writing manifest file 'AddTest.egg-info/SOURCES.txt'
running build_ext
Command line entry point called.

Note the Command line entry point called. which means it's invoking the console script it generates from my __main__.py (or maybe just calling python -m addtest).

Why is setup.py calling the console script when I want it to run tests? Further inspection of the script's execution shows that sys.argv is ['setup.py','test'] - why?

Answer 1

The test scanner in setuptools will look for tests in any *.py file found in your sub-directories, except for __init__.py. Yes, this includes __main__.py, it will call __import__() on it, causing its main suite to be executed.

If you want to be able to run python -m addtest and have that run your __main__.py code, you may want to add the standard 'run only if this is really main' protection:

if __name__ == "__main__":
   ...

(then, if you do python -m the code will run, but it won't run if the file is loaded by setup.py test)