cibuildwheel/test/03_before_build/setup.py

from setuptools import setup, Extension
import sys, os

# assert that the Python version as written to pythonversion.txt in the CIBW_BEFORE_BUILD step
# is the same one as is currently running.
version_file = 'c:\\pythonversion.txt' if sys.platform == 'win32' else '/tmp/pythonversion.txt'
with open(version_file) as f:
    stored_version = f.read()
print('stored_version', stored_version)
print('sys.version', sys.version)
assert stored_version == sys.version

# check that the executable also was written
executable_file = 'c:\\pythonexecutable.txt' if sys.platform == 'win32' else '/tmp/pythonexecutable.txt'
with open(executable_file) as f:
    stored_executable = f.read()
print('stored_executable', stored_executable)
print('sys.executable', sys.executable)
# windows/mac are case insensitive
assert os.path.realpath(stored_executable).lower() == os.path.realpath(sys.executable).lower()

setup(
    name="spam",
    ext_modules=[Extension('spam', sources=['spam.c'])],
    version="0.1.0",
)