Add timeout to test_build_meta

setuptools/tests/test_build_meta.py

@@ -1,7 +1,9 @@
 import os
 import shutil
+import signal
 import tarfile
 import importlib
+import contextlib
 from concurrent import futures
 import re
 
@@ -11,6 +13,9 @@
 from .textwrap import DALS
 
 
+TIMEOUT = int(os.getenv("TIMEOUT_BACKEND_TEST", "180"))  # in seconds
+
+
 class BuildBackendBase:
     def __init__(self, cwd='.', env={}, backend_name='setuptools.build_meta'):
         self.cwd = cwd
@@ -31,10 +36,23 @@ def __getattr__(self, name):
         def method(*args, **kw):
             root = os.path.abspath(self.cwd)
             caller = BuildBackendCaller(root, self.env, self.backend_name)
-            return self.pool.submit(caller, name, *args, **kw).result()
+            pid = None
+            try:
+                pid = self.pool.submit(os.getpid).result(TIMEOUT)
+                return self.pool.submit(caller, name, *args, **kw).result(TIMEOUT)
+            except futures.TimeoutError:
+                self.pool.shutdown(wait=False)  # doesn't stop already running processes
+                self._kill(pid)
+                pytest.xfail(f"Backend did not respond before timeout ({TIMEOUT} s)")
 
         return method
 
+    def _kill(self, pid):
+        if pid is None:
+            return
+        with contextlib.suppress(ProcessLookupError, OSError):
+            os.kill(pid, signal.SIGTERM if os.name == "nt" else signal.SIGKILL)
+
 
 class BuildBackendCaller(BuildBackendBase):
     def __init__(self, *args, **kwargs):

tox.ini

@@ -14,6 +14,7 @@ usedevelop = True
 extras = testing
 passenv =
 	SETUPTOOLS_USE_DISTUTILS
+	TIMEOUT_BACKEND_TEST  # timeout (in seconds) for test_build_meta
 	windir  # required for test_pkg_resources
 	# honor git config in pytest-perf
 	HOME