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I have a simple python module (let's call it M1) which is standalone (the only import is to collections), inside a package containing ugliness. Part of the ugliness is in the package's __init__.py file. But M1 is nice and clean, and contains some test functions for use with py.test.

Now, I would like to test M1 and ignore all the ugliness. But py.test wants to run __init__.py -- is there any way I can prevent this? I really can't fix the __init__.py file at this time, and I want to keep my test functions contained right alongside the M1 module contents itself.

I've already read this SO question: `py.test` and `__init__.py` files which explains the issue but offers no solution.

my __init__.py file looks something like this; it's just promoting items into package scope:

from .M1 import CleanThing1, CleanThing2
from .Evil1 import UglyThing1, UglyThing2

and the problem is that the Evil1 module requires some PYTHONPATH hackery to execute properly, and when I run

py.test mymodule/M1.py

it fails because of the Evil1 module. But I just want to test the M1 module right now.

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Jason S
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2 Answers2

2

You can make the __init__.py file aware of py.test as described here.

So basically create a mymodule/conftest.py file with the following content

def pytest_configure(config):
    import sys
    sys._called_from_test = True

def pytest_unconfigure(config):
    del sys._called_from_test

and in the __init__.py file simply check if you are inside the py.test session like

import sys
if hasattr(sys, '_called_from_test'):
    # called from within a test run
    pass
else:
    # failing imports
    from .M1 import CleanThing1, CleanThing2
    from .Evil1 import UglyThing1, UglyThing2

This way I could run py.test mymodule/M1.py without the import errors.

The package structure now looks like (I hope that resembles your structure)

package
   |   
   |- __init__.py
   |- mymodule/
         |- M1.py
         |- conftest.py
Jakob
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  • how do you create a mymodule/conftest.py? My module name is M1.py (it's a module, not a package)... would I have to create M1/conftest.py? – Jason S Jan 02 '15 at 21:57
  • what do you mean by how to create the conftest.py file? I've add a package structure to my answer, hope this resembles yours. – Jakob Jan 02 '15 at 22:25
  • oh, thanks. The drawing really helps! It was a problem in terminology; if I understand Python correctly, your "mymodule" should really be a subpackage. Or I am misunderstanding the terminology. – Jason S Jan 03 '15 at 15:12
  • You are totally right, sorry for the wrong terminology. I was just referring to your `py.test mymodule/M1.py` call. – Jakob Jan 03 '15 at 18:42
0

It's not py.test that wants to run __init.py__, but the Python interpreter. The rule that __init__.py is executed is part of the Python language definition, and any way around it will necessarily be a hack.

In this case, I suggest that you definte a stubbed Evil1 module of your own, and let M1 import that one instead.

Sneftel
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