Running pytest with cython - how to compile cython modules in pytest?

问题:

I have a project organized as follows:

where api.py imports cythonized extensions:

 """api.py""""  from _cython_foo import cython_fun 

My setup script builds the .pyx source inplace correctly and I'm able to use cython_fun in the installed package:

import project.module1.api as module1 module1.cython_fun()    # OK 

However, pytest complains that it cannot import the cython module since the compiled binaries are not in place until I invoke setup.

project/module1/api.py:2: in <module>     from _cython_foo import cython_fun E   ImportError: No module named _cython_foo 

It seems like bad style to leave a bunch of precompiled binaries inside my project directory that pytest depends on, so is there a conventional way to have pytest temporarily build the cython modules for the purpose of my unit tests only?

回答1:

I know about two ways of marrying pytest with cythonized extensions:

1. Do not invoke the tests via pytest directly; instead, use in-place test command with the setup script. To do that, install pytest-runner plugin that adds a pytest command:

   $ pip install pytest-runner 

   Now you should be able to invoke the tests with pytest by issuing

   $ python setup.py pytest 

   This approach, however, will require some changes in the way the command line args are passed: the pendant to command

   $ pytest --arg1 --arg2 

   will be

   $ python setup.py pytest --addopts "--arg1 --arg2" 

2. If you want to continue using the pytest command: install the project in development mode (ideally, in a virtualenv).

   (myenv) $ pip install --editable dir/ 

   where dir/ is the directory containing the setup.py script. Now the extensions will be prebuilt and pytest will be able to resolve them.

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