Bump version: v1.3.0

Add support for GitHub Actions

.github/workflows/test.yml

@@ -0,0 +1,29 @@
+name: Test
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    name: Test cibuildwheel on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-18.04, windows-latest, macos-latest]
+        python_version: ['3.7']
+    steps:
+    - uses: actions/checkout@v1
+    - uses: actions/setup-python@v1
+      name: Install Python ${{ matrix.python_version }}
+      with:
+        python-version: ${{ matrix.python_version }}
+
+    - name: Install dependencies
+      run: |
+        python -m pip install -r requirements-dev.txt
+    - name: Install Visual C++ for Python 2.7
+      if: startsWith(matrix.os, 'windows')
+      run: |
+        choco install vcpython27 -f -y
+    - name: Test cibuildwheel
+      run: |
+        python ./bin/run_tests.py

.travis.yml

@@ -34,7 +34,8 @@ jobs:
       env:
         - PYTHON=C:\\Python35\\python
 
-    - name: Linux | s390x | Python 3.5
+    - &linux_s390x_35
+      name: Linux | s390x | Python 3.5
       language: python
       python: 3.5
       services: docker
@@ -43,12 +44,7 @@ jobs:
 
   allow_failures:
     # must repeat the s390x job above exactly to match
-    - name: Linux | s390x | Python 3.5
-      language: python
-      python: 3.5
-      services: docker
-      arch: s390x
-      env: PYTHON=python
+    - *linux_s390x_35
 
 install: $PYTHON -m pip install -r requirements-dev.txt
 

CI.md

@@ -1,10 +1,10 @@
 This is a summary of the Python versions and platforms covered by the different CI platforms:
 
-|          | 3.5              | 3.6              | 3.7                   | 3.8              |
-|----------|------------------|------------------|-----------------------|------------------|
-| Linux    | Travis CI        | CircleCI         | AppVeyor              | Azure Pipelines  |
-| macOS    | Azure Pipelines  | CircleCI         | Travis CI¹ / CircleCI | Azure Pipelines  |
-| Windows  | TravisCI         | Azure Pipelines  | AppVeyor              | Azure Pipelines  |
+|          | 3.5              | 3.6              | 3.7                                               | 3.8              |
+|----------|------------------|------------------|---------------------------------------------------|------------------|
+| Linux    | Travis CI        | CircleCI         | AppVeyor / GitHub Actions                         | Azure Pipelines  |
+| macOS    | Azure Pipelines  | CircleCI         | AppVeyor / Travis CI¹ / CircleCI / GitHub Actions | Azure Pipelines  |
+| Windows  | TravisCI         | Azure Pipelines  | AppVeyor / GitHub Actions                         | Azure Pipelines  |
 
 > ¹ Python version not really pinned, but dependent on the (default) version of image used.
 

README.md

@@ -9,7 +9,7 @@ cibuildwheel
 
 Python wheels are great. Building them across **Mac, Linux, Windows**, on **multiple versions of Python**, is not.
 
-`cibuildwheel` is here to help. `cibuildwheel` runs on your CI server - currently it supports Azure Pipelines, Travis CI, AppVeyor, and CircleCI - and it builds and tests your wheels across all of your platforms.
+`cibuildwheel` is here to help. `cibuildwheel` runs on your CI server - currently it supports Azure Pipelines, Travis CI, AppVeyor, GitHub Actions and CircleCI - and it builds and tests your wheels across all of your platforms.
 
 
 What does it do?
@@ -35,13 +35,14 @@ What does it do?
 Usage
 -----
 
-`cibuildwheel` currently works on **Travis CI**, **Azure Pipelines** and **AppVeyor** to build wheels for all three supported platforms (Linux, macOS, Windows). On **CircleCI** Linux and macOS wheels can be built.
+`cibuildwheel` currently works on **Travis CI**, **Azure Pipelines**, **AppVeyor** and **GitHub Actions** to build wheels for all three supported platforms (Linux, macOS, Windows). On **CircleCI** Linux and macOS wheels can be built.
 
 |                 | Linux | macOS | Windows |
 |-----------------|-------|-------|---------|
 | Azure Pipelines | ✅    | ✅    | ✅      |
 | Travis CI       | ✅    | ✅    | ✅      |
 | AppVeyor        | ✅    | ✅    | ✅      |
+| GitHub Actions  | ✅    | ✅    | ✅      |
 | CircleCI        | ✅    | ✅    |         |
 
 `cibuildwheel` is not intended to run on your development machine. Because it uses system Python from Python.org it will try to install packages globally - not what you expect from a build tool! Instead, isolated CI services like Travis CI, CircleCI, Azure Pipelines and AppVeyor are ideal.
@@ -76,7 +77,7 @@ env:
     # Note: TWINE_PASSWORD is set to a PyPI API token in Travis settings
 
 install:
-  - python3 -m pip install cibuildwheel==1.2.0
+  - python3 -m pip install cibuildwheel==1.3.0
 
 script:
   # build the wheels, put them into './wheelhouse'
@@ -105,6 +106,7 @@ Options
 |   | [`CIBW_REPAIR_WHEEL_COMMAND`](https://cibuildwheel.readthedocs.io/en/stable/options/#repair-wheel-command)  | Execute a shell command to repair each (non-pure Python) built wheel |
 |   | [`CIBW_MANYLINUX_X86_64_IMAGE`](https://cibuildwheel.readthedocs.io/en/stable/options/#manylinux-image)  [`CIBW_MANYLINUX_I686_IMAGE`](https://cibuildwheel.readthedocs.io/en/stable/options/#manylinux-image)  [`CIBW_MANYLINUX_PYPY_X86_64_IMAGE`](https://cibuildwheel.readthedocs.io/en/stable/options/#manylinux-image)  | Specify alternative manylinux docker images |
 | **Testing** | [`CIBW_TEST_COMMAND`](https://cibuildwheel.readthedocs.io/en/stable/options/#test-command)  | Execute a shell command to test each built wheel |
+|   | [`CIBW_BEFORE_TEST`](https://cibuildwheel.readthedocs.io/en/stable/options/#before-test)  | Execute shell command to prepare test environment |
 |   | [`CIBW_TEST_REQUIRES`](https://cibuildwheel.readthedocs.io/en/stable/options/#test-requires)  | Install Python dependencies before running the tests |
 |   | [`CIBW_TEST_EXTRAS`](https://cibuildwheel.readthedocs.io/en/stable/options/#test-extras)  | Install your wheel for testing using extras_require |
 | **Other** | [`CIBW_BUILD_VERBOSITY`](https://cibuildwheel.readthedocs.io/en/stable/options/#build-verbosity)  | Increase/decrease the output of pip wheel |
@@ -124,6 +126,7 @@ Here are some repos that use cibuildwheel.
 - [apriltags2-ethz](https://github.com/safijari/apriltags2_ethz)
 - [TgCrypto](https://github.com/pyrogram/tgcrypto)
 - [Twisted](https://github.com/twisted/twisted)
+- [gmic-py](https://github.com/dtschump/gmic-py)
 
 > Add your repo here! Send a PR.
 
@@ -139,6 +142,16 @@ This is similar to static linking, so it might have some licence implications. C
 Changelog
 =========
 
+### 1.3.0
+
+_12 March 2020_
+
+- ✨ Add support for building on Github Actions! Check out the
+  [docs](https://cibuildwheel.readthedocs.io/en/stable/setup/#github-actions)
+  for information on how to set it up. (#194)
+- ✨ Add the `CIBW_BEFORE_TEST` option, which lets you run a command to
+  prepare the environment before your tests are run. (#242)
+
 ### 1.2.0
 
 _8 March 2020_

cibuildwheel/__init__.py

@@ -1 +1 @@
-__version__ = '1.2.0'
+__version__ = '1.3.0'

cibuildwheel/__main__.py

@@ -77,12 +77,12 @@ def main():
     if args.platform != 'auto':
         platform = args.platform
     else:
-        ci = strtobool(os.environ.get('CI', 'false')) or 'BITRISE_BUILD_NUMBER' in os.environ or 'AZURE_HTTP_USER_AGENT' in os.environ
+        ci = strtobool(os.environ.get('CI', 'false')) or 'BITRISE_BUILD_NUMBER' in os.environ or 'AZURE_HTTP_USER_AGENT' in os.environ or 'GITHUB_WORKFLOW' in os.environ
         if not ci:
             print('cibuildwheel: Unable to detect platform. cibuildwheel should run on your CI server, '
-                  'Travis CI, AppVeyor, Azure Pipelines and CircleCI are supported. You can run on your '
-                  'development machine or other CI providers using the --platform argument. Check --help '
-                  'output for more information.',
+                  'Travis CI, AppVeyor, Azure Pipelines, GitHub Actions and CircleCI are supported. You '
+                  'can run on your development machine or other CI providers using the --platform argument. '
+                  'Check --help output for more information.',
                   file=sys.stderr)
             exit(2)
         if sys.platform.startswith('linux'):
@@ -113,6 +113,7 @@ def main():
         repair_command_default = ''
     repair_command = get_option_from_environment('CIBW_REPAIR_WHEEL_COMMAND', platform=platform, default=repair_command_default)
     environment_config = get_option_from_environment('CIBW_ENVIRONMENT', platform=platform, default='')
+    before_test = get_option_from_environment('CIBW_BEFORE_TEST', platform=platform, default='')
 
     if test_extras:
         test_extras = '[{0}]'.format(test_extras)
@@ -154,6 +155,7 @@ def main():
         build_selector=build_selector,
         repair_command=repair_command,
         environment=environment,
+        before_test=before_test
     )
 
     if platform == 'linux':

cibuildwheel/linux.py

@@ -68,7 +68,7 @@ def get_python_configurations(build_selector):
     return [c for c in python_configurations if matches_platform(c.identifier) and build_selector(c.identifier)]
 
 
-def build(project_dir, output_dir, test_command, test_requires, test_extras, before_build, build_verbosity, build_selector, repair_command, environment, manylinux_images):
+def build(project_dir, output_dir, test_command, before_test, test_requires, test_extras, before_build, build_verbosity, build_selector, repair_command, environment, manylinux_images):
     try:
         subprocess.check_call(['docker', '--version'])
     except Exception:
@@ -154,6 +154,10 @@ def build(project_dir, output_dir, test_command, test_requires, test_extras, bef
 
                         echo "Running tests using `which python`"
 
+                        if [ ! -z {before_test} ]; then
+                            sh -c {before_test}
+                        fi
+
                         # Install the wheel we just built
                         # Note: If auditwheel produced two wheels, it's because the earlier produced wheel
                         # conforms to multiple manylinux standards. These multiple versions of the wheel are
@@ -202,6 +206,9 @@ def build(project_dir, output_dir, test_command, test_requires, test_extras, bef
             environment_exports='\n'.join(environment.as_shell_commands()),
             uid=os.getuid(),
             gid=os.getgid(),
+            before_test=shlex.quote(
+                prepare_command(before_test, project='/project') if before_test else ''
+            ),
         )
 
         container_name = 'cibuildwheel-{}'.format(uuid.uuid4())

cibuildwheel/macos.py

@@ -105,7 +105,7 @@ def install_pypy(version, url):
     return installation_bin_path
 
 
-def build(project_dir, output_dir, test_command, test_requires, test_extras, before_build, build_verbosity, build_selector, repair_command, environment):
+def build(project_dir, output_dir, test_command, before_test, test_requires, test_extras, before_build, build_verbosity, build_selector, repair_command, environment):
     abs_project_dir = os.path.abspath(project_dir)
     temp_dir = tempfile.mkdtemp(prefix='cibuildwheel')
     built_wheel_dir = os.path.join(temp_dir, 'built_wheel')
@@ -214,6 +214,10 @@ def build(project_dir, output_dir, test_command, test_requires, test_extras, bef
             # check that we are using the Python from the virtual environment
             call(['which', 'python'], env=virtualenv_env)
 
+            if before_test:
+                before_test_prepared = prepare_command(before_test, project=abs_project_dir)
+                call(before_test_prepared, env=virtualenv_env, shell=True)
+
             # install the wheel
             call(['pip', 'install', repaired_wheel + test_extras], env=virtualenv_env)
 

cibuildwheel/windows.py

@@ -86,7 +86,7 @@ def install_pypy(version, arch, url):
     return installation_path
 
 
-def build(project_dir, output_dir, test_command, test_requires, test_extras, before_build, build_verbosity, build_selector, repair_command, environment):
+def build(project_dir, output_dir, test_command, before_test, test_requires, test_extras, before_build, build_verbosity, build_selector, repair_command, environment):
     abs_project_dir = os.path.abspath(project_dir)
     temp_dir = tempfile.mkdtemp(prefix='cibuildwheel')
     built_wheel_dir = os.path.join(temp_dir, 'built_wheel')
@@ -192,6 +192,10 @@ def build(project_dir, output_dir, test_command, test_requires, test_extras, bef
             # check that we are using the Python from the virtual environment
             shell(['which', 'python'], env=virtualenv_env)
 
+            if before_test:
+                before_test_prepared = prepare_command(before_test, project=abs_project_dir)
+                shell([before_test_prepared], env=virtualenv_env)
+
             # install the wheel
             shell(['pip', 'install', repaired_wheel + test_extras], env=virtualenv_env)
 

docs/options.md

@@ -343,6 +343,33 @@ Platform-specific variants also available:<br/>
 CIBW_TEST_EXTRAS: test,qt
 ```
 
+### `CIBW_BEFORE_TEST` {: #before-test}
+> Execute a shell command before testing each wheel
+
+A shell command to run in **each** test virtual environment, before your wheel is installed and tested. This is useful if you need to install a non pip package, change values of environment variables
+or perform multi step pip installation (e.g. installing `scikit-build` or `cython` before install test package)
+
+The active Python binary can be accessed using `python`, and pip with `pip`; `cibuildwheel` makes sure the right version of Python and pip will be executed. `{project}` can be used as a placeholder for the absolute path to the project's root and will be replaced by `cibuildwheel`.
+
+The command is run in a shell, so you can write things like `cmd1 && cmd2`.
+
+Platform-specific variants also available:<br/>
+ `CIBW_BEFORE_TEST_MACOS` | `CIBW_BEFORE_TEST_WINDOWS` | `CIBW_BEFORE_TEST_LINUX`
+
+#### Examples
+```yaml
+# install test dependencies with overwritten environment variables. 
+CIBW_BEFORE_TEST: CC=gcc CXX=g++ pip install -r requirements.txt
+
+# chain commands using &&
+CIBW_BEFORE_TEST: rm -rf ./data/cache && mkdir -p ./data/cache
+
+# install non pip python package 
+CIBW_BEFORE_TEST: cd some_dir; ./configure; make; make install
+
+# install python packages that are required to install test dependencies
+CIBW_BEFORE_TEST: pip install cmake scikit-build
+```
 
 ## Other
 

docs/setup.md

@@ -2,9 +2,22 @@
 title: 'Setup'
 ---
 
+# GitHub Actions [linux/mac/windows] {: #github-actions}
+
+To build Linux, Mac, and Windows wheels using Github Actions, create a `.github/workflows/build.yml` file in your repo.
+
+> build.yml
+```yaml
+{% include "../examples/github-minimal.yml" %}
+```
+
+Commit this file, and push to Github - either to your default branch, or to a PR branch. The build should start automatically.
+
+For more info on this file, check out the [docs](https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions).
+
 # Azure Pipelines [linux/mac/windows] {: #azure-pipelines}
 
-Using Azure pipelines, you can build all three platforms on the same service. Create a `azure-pipelines.yml` file in your repo.
+To build Linux, Mac, and Windows wheels on Azure Pipelines, create a `azure-pipelines.yml` file in your repo.
 
 > azure-pipelines.yml
 ```yaml

examples/appveyor-minimal.yml

@@ -12,7 +12,7 @@ stack: python 3.7
 init:
 - cmd: set PATH=C:\Python37;C:\Python37\Scripts;%PATH%
 
-install: python -m pip install cibuildwheel==1.2.0
+install: python -m pip install cibuildwheel==1.3.0
 
 build_script: python -m cibuildwheel --output-dir wheelhouse
 

examples/azure-pipelines-minimal.yml

@@ -5,7 +5,7 @@ jobs:
     - task: UsePythonVersion@0
     - bash: |
         python3 -m pip install --upgrade pip
-        pip3 install cibuildwheel==1.2.0
+        pip3 install cibuildwheel==1.3.0
         cibuildwheel --output-dir wheelhouse .
     - task: PublishBuildArtifacts@1
       inputs: {pathtoPublish: 'wheelhouse'}
@@ -16,7 +16,7 @@ jobs:
     - task: UsePythonVersion@0
     - bash: |
         python3 -m pip install --upgrade pip
-        pip3 install cibuildwheel==1.2.0
+        pip3 install cibuildwheel==1.3.0
         cibuildwheel --output-dir wheelhouse .
     - task: PublishBuildArtifacts@1
       inputs: {pathtoPublish: 'wheelhouse'}
@@ -29,7 +29,7 @@ jobs:
       displayName: Install Visual C++ for Python 2.7
     - bash: |
         python -m pip install --upgrade pip
-        pip install cibuildwheel==1.2.0
+        pip install cibuildwheel==1.3.0
         cibuildwheel --output-dir wheelhouse .
     - task: PublishBuildArtifacts@1
       inputs: {pathtoPublish: 'wheelhouse'}

examples/circleci-minimal.yml

@@ -11,7 +11,7 @@ jobs:
       - run:
           name: Build the Linux wheels.
           command: |
-            pip3 install --user cibuildwheel==1.2.0
+            pip3 install --user cibuildwheel==1.3.0
             cibuildwheel --output-dir wheelhouse
       - store_artifacts:
           path: wheelhouse/
@@ -25,7 +25,7 @@ jobs:
       - run:
           name: Build the OS X wheels.
           command: |
-            pip3 install --user cibuildwheel==1.2.0
+            pip3 install --user cibuildwheel==1.3.0
             cibuildwheel --output-dir wheelhouse
       - store_artifacts:
           path: wheelhouse/

examples/github-minimal.yml

@@ -0,0 +1,37 @@
+name: Build
+
+on: [push, pull_request]
+
+jobs:
+  build_wheels:
+    name: Build wheel on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-18.04, windows-latest, macos-latest]
+
+    steps:
+    - uses: actions/checkout@v1
+
+    - uses: actions/setup-python@v1
+      name: Install Python
+      with:
+        python-version: '3.7'
+
+    - name: Install cibuildwheel
+      run: |
+        python -m pip install cibuildwheel==1.3.0
+
+    - name: Install Visual C++ for Python 2.7
+      if: startsWith(matrix.os, 'windows')
+      run: |
+        choco install vcpython27 -f -y
+
+    - name: Build wheel
+      run: |
+        python -m cibuildwheel --output-dir wheelhouse
+
+    - uses: actions/upload-artifact@v1
+      with:
+        name: wheels
+        path: ./wheelhouse

examples/travis-ci-deploy-only.yml

@@ -25,7 +25,7 @@ env:
     # Note: TWINE_PASSWORD is set to a PyPI API token in Travis settings
 
 install:
-  - python3 -m pip install cibuildwheel==1.2.0
+  - python3 -m pip install cibuildwheel==1.3.0
 
 script:
   # build the wheels, put them into './wheelhouse'

examples/travis-ci-minimal.yml

@@ -26,7 +26,7 @@ jobs:
         - ln -s /c/Python38/python.exe /c/Python38/python3.exe
 
 install:
-  - python3 -m pip install cibuildwheel==1.2.0
+  - python3 -m pip install cibuildwheel==1.3.0
 
 script:
   # build the wheels, put them into './wheelhouse'

examples/travis-ci-test-and-deploy.yml

@@ -56,7 +56,7 @@ jobs:
     - stage: deploy
       name: Build and deploy Linux wheels
       services: docker
-      install: python3 -m pip install cibuildwheel==1.2.0
+      install: python3 -m pip install cibuildwheel==1.3.0
       script: python3 -m cibuildwheel --output-dir wheelhouse
       after_success: |
         python3 -m pip install twine
@@ -66,7 +66,7 @@ jobs:
       name: Build and deploy macOS wheels
       os: osx
       language: shell
-      install: python3 -m pip install cibuildwheel==1.2.0
+      install: python3 -m pip install cibuildwheel==1.3.0
       script: python3 -m cibuildwheel --output-dir wheelhouse
       after_success: |
         python3 -m pip install twine
@@ -76,7 +76,7 @@ jobs:
       name: Build and deploy Windows wheels
       os: windows
       language: shell
-      install: python3 -m pip install cibuildwheel==1.2.0
+      install: python3 -m pip install cibuildwheel==1.3.0
       script: python3 -m cibuildwheel --output-dir wheelhouse
       after_success: |
         python3 -m pip install twine

setup.cfg

@@ -1,24 +1,3 @@
-[bumpversion]
-current_version = 1.1.0
-commit = True
-tag = True
-message = Bump version
-
-[bumpversion:file:setup.py]
-
-[bumpversion:file:cibuildwheel/__init__.py]
-
-[bumpversion:file:README.md]
-search = cibuildwheel=={current_version}
-replace = cibuildwheel=={new_version}
-
-[bumpversion:file:docs/setup.md]
-search = cibuildwheel=={current_version}
-replace = cibuildwheel=={new_version}
-
-[bdist_wheel]
-universal = 1
-
 [flake8]
 ignore = E501,W503
 application-import-names = cibuildwheel

setup.py

@@ -13,7 +13,7 @@ with io.open(os.path.join(this_directory, 'README.md'), encoding='utf-8') as f:
 
 setup(
     name='cibuildwheel',
-    version='1.2.0',
+    version='1.3.0',
     install_requires=['bashlex!=0.13'],
     description="Build Python wheels on CI with minimal configuration.",
     long_description=long_description,

test/11_before_test/cibuildwheel_test.py

@@ -0,0 +1,23 @@
+import os
+import utils
+
+
+def test():
+    project_dir = os.path.dirname(__file__)
+
+    # build the wheels
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env={
+        # write python version information to a temporary file, this is
+        # checked in setup.py
+        'CIBW_BEFORE_TEST': '''python -c "import sys; open('/tmp/pythonversion.txt', 'w').write(sys.version)" && python -c "import sys; open('/tmp/pythonprefix.txt', 'w').write(sys.prefix)"''',
+        'CIBW_BEFORE_TEST_WINDOWS': '''python -c "import sys; open('c:\\pythonversion.txt', 'w').write(sys.version)" && python -c "import sys; open('c:\\pythonprefix.txt', 'w').write(sys.prefix)"''',
+        'CIBW_TEST_REQUIRES': 'nose',
+        # the 'false ||' bit is to ensure this command runs in a shell on
+        # mac/linux.
+        'CIBW_TEST_COMMAND': 'false || nosetests {project}/test',
+        'CIBW_TEST_COMMAND_WINDOWS': 'nosetests {project}/test',
+    })
+
+    # also check that we got the right wheels
+    expected_wheels = utils.expected_wheels('spam', '0.1.0')
+    assert set(actual_wheels) == set(expected_wheels)

test/11_before_test/setup.py

@@ -0,0 +1,8 @@
+from setuptools import setup, Extension
+
+
+setup(
+    name="spam",
+    ext_modules=[Extension('spam', sources=['spam.c'])],
+    version="0.1.0",
+)

test/11_before_test/spam.c

@@ -0,0 +1,48 @@
+#include <Python.h>
+
+static PyObject *
+spam_system(PyObject *self, PyObject *args)
+{
+    const char *command;
+    int sts;
+
+    if (!PyArg_ParseTuple(args, "s", &command))
+        return NULL;
+    sts = system(command);
+    return PyLong_FromLong(sts);
+}
+
+/* Module initialization */
+
+#if PY_MAJOR_VERSION >= 3
+    #define MOD_INIT(name) PyMODINIT_FUNC PyInit_##name(void)
+    #define MOD_DEF(m, name, doc, methods, module_state_size) \
+        static struct PyModuleDef moduledef = { \
+            PyModuleDef_HEAD_INIT, name, doc, module_state_size, methods, }; \
+        m = PyModule_Create(&moduledef);
+    #define MOD_RETURN(m) return m;
+#else
+    #define MOD_INIT(name) PyMODINIT_FUNC init##name(void)
+    #define MOD_DEF(m, name, doc, methods, module_state_size) \
+        m = Py_InitModule3(name, methods, doc);
+    #define MOD_RETURN(m) return;
+#endif
+
+static PyMethodDef module_methods[] = {
+    {"system", (PyCFunction)spam_system, METH_VARARGS, 
+     "Execute a shell command."},
+    {NULL}  /* Sentinel */
+};
+
+MOD_INIT(spam)
+{
+    PyObject* m;
+
+    MOD_DEF(m, 
+            "spam", 
+            "Example module", 
+            module_methods,
+            -1)
+
+    MOD_RETURN(m)
+}

test/11_before_test/test/spam_test.py

@@ -0,0 +1,28 @@
+import sys
+import os
+from unittest import TestCase
+
+
+class TestBeforeTest(TestCase):
+    def test_version(self):
+        # assert that the Python version as written to pythonversion.txt in the CIBW_BEFORE_TEST step
+        # is the same one as is currently running.
+        # because of use symlinks in MacOS run this test is also need
+        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
+
+    def test_prefix(self):
+        # check that the prefix also was written
+        prefix_file = 'c:\\pythonprefix.txt' if sys.platform == 'win32' else '/tmp/pythonprefix.txt'
+        with open(prefix_file) as f:
+            stored_prefix = f.read()
+        print('stored_prefix', stored_prefix)
+        print('sys.prefix', sys.prefix)
+        #  Works around path-comparison bugs caused by short-paths on Windows e.g.
+        #  vssadm~1 instead of vssadministrator
+
+        assert os.stat(stored_prefix) == os.stat(sys.prefix)

unit_test/main_tests/main_platform_test.py

@@ -11,6 +11,7 @@ def test_unknown_platform_non_ci(monkeypatch, capsys):
     monkeypatch.delenv('CI', raising=False)
     monkeypatch.delenv('BITRISE_BUILD_NUMBER', raising=False)
     monkeypatch.delenv('AZURE_HTTP_USER_AGENT', raising=False)
+    monkeypatch.delenv('GITHUB_WORKFLOW', raising=False)
 
     with pytest.raises(SystemExit) as exit:
         main()