1 files changed, 89 insertions, 0 deletions
diff --git a/Lib/test/test_cppext/__init__.py b/Lib/test/test_cppext/__init__.py
new file mode 100644
index 0000000..f3d32a3
--- /dev/null
+++ b/Lib/test/test_cppext/__init__.py
@@ -0,0 +1,89 @@
+# gh-91321: Build a basic C++ test extension to check that the Python C API is
+# compatible with C++ and does not emit C++ compiler warnings.
+import os.path
+import shutil
+import sys
+import unittest
+import subprocess
+import sysconfig
+from test import support
+from test.support import os_helper
+
+
+MS_WINDOWS = (sys.platform == 'win32')
+SOURCE = os.path.join(os.path.dirname(__file__), 'extension.cpp')
+SETUP = os.path.join(os.path.dirname(__file__), 'setup.py')
+
+
+@support.requires_subprocess()
+class TestCPPExt(unittest.TestCase):
+    def test_build_cpp11(self):
+        self.check_build(False, '_testcpp11ext')
+
+    def test_build_cpp03(self):
+        self.check_build(True, '_testcpp03ext')
+
+    # With MSVC, the linker fails with: cannot open file 'python311.lib'
+    # https://github.com/python/cpython/pull/32175#issuecomment-1111175897
+    @unittest.skipIf(MS_WINDOWS, 'test fails on Windows')
+    # Building and running an extension in clang sanitizing mode is not
+    # straightforward
+    @unittest.skipIf(
+        '-fsanitize' in (sysconfig.get_config_var('PY_CFLAGS') or ''),
+        'test does not work with analyzing builds')
+    # the test uses venv+pip: skip if it's not available
+    @support.requires_venv_with_pip()
+    def check_build(self, std_cpp03, extension_name):
+        venv_dir = 'env'
+        with support.setup_venv_with_pip_setuptools_wheel(venv_dir) as python_exe:
+            self._check_build(std_cpp03, extension_name, python_exe)
+
+    def _check_build(self, std_cpp03, extension_name, python_exe):
+        pkg_dir = 'pkg'
+        os.mkdir(pkg_dir)
+        shutil.copy(SETUP, os.path.join(pkg_dir, os.path.basename(SETUP)))
+        shutil.copy(SOURCE, os.path.join(pkg_dir, os.path.basename(SOURCE)))
+
+        def run_cmd(operation, cmd):
+            env = os.environ.copy()
+            env['CPYTHON_TEST_CPP_STD'] = 'c++03' if std_cpp03 else 'c++11'
+            env['CPYTHON_TEST_EXT_NAME'] = extension_name
+            if support.verbose:
+                print('Run:', ' '.join(cmd))
+                subprocess.run(cmd, check=True, env=env)
+            else:
+                proc = subprocess.run(cmd,
+                                      env=env,
+                                      stdout=subprocess.PIPE,
+                                      stderr=subprocess.STDOUT,
+                                      text=True)
+                if proc.returncode:
+                    print(proc.stdout, end='')
+                    self.fail(
+                        f"{operation} failed with exit code {proc.returncode}")
+
+        # Build and install the C++ extension
+        cmd = [python_exe, '-X', 'dev',
+               '-m', 'pip', 'install', '--no-build-isolation',
+               os.path.abspath(pkg_dir)]
+        run_cmd('Install', cmd)
+
+        # Do a reference run. Until we test that running python
+        # doesn't leak references (gh-94755), run it so one can manually check
+        # -X showrefcount results against this baseline.
+        cmd = [python_exe,
+               '-X', 'dev',
+               '-X', 'showrefcount',
+               '-c', 'pass']
+        run_cmd('Reference run', cmd)
+
+        # Import the C++ extension
+        cmd = [python_exe,
+               '-X', 'dev',
+               '-X', 'showrefcount',
+               '-c', f"import {extension_name}"]
+        run_cmd('Import', cmd)
+
+
+if __name__ == "__main__":
+    unittest.main()