gh-108388: Convert test_concurrent_futures to package (#108401)

Convert test_concurrent_futures to a package of sub-tests.

Lib/test/test_concurrent_futures/test_init.py

@@ -0,0 +1,117 @@
+import contextlib
+import logging
+import queue
+import time
+import unittest
+from concurrent.futures._base import BrokenExecutor
+from logging.handlers import QueueHandler
+
+from test import support
+
+from .util import ExecutorMixin, create_executor_tests, setup_module
+
+
+INITIALIZER_STATUS = 'uninitialized'
+
+def init(x):
+    global INITIALIZER_STATUS
+    INITIALIZER_STATUS = x
+
+def get_init_status():
+    return INITIALIZER_STATUS
+
+def init_fail(log_queue=None):
+    if log_queue is not None:
+        logger = logging.getLogger('concurrent.futures')
+        logger.addHandler(QueueHandler(log_queue))
+        logger.setLevel('CRITICAL')
+        logger.propagate = False
+    time.sleep(0.1)  # let some futures be scheduled
+    raise ValueError('error in initializer')
+
+
+class InitializerMixin(ExecutorMixin):
+    worker_count = 2
+
+    def setUp(self):
+        global INITIALIZER_STATUS
+        INITIALIZER_STATUS = 'uninitialized'
+        self.executor_kwargs = dict(initializer=init,
+                                    initargs=('initialized',))
+        super().setUp()
+
+    def test_initializer(self):
+        futures = [self.executor.submit(get_init_status)
+                   for _ in range(self.worker_count)]
+
+        for f in futures:
+            self.assertEqual(f.result(), 'initialized')
+
+
+class FailingInitializerMixin(ExecutorMixin):
+    worker_count = 2
+
+    def setUp(self):
+        if hasattr(self, "ctx"):
+            # Pass a queue to redirect the child's logging output
+            self.mp_context = self.get_context()
+            self.log_queue = self.mp_context.Queue()
+            self.executor_kwargs = dict(initializer=init_fail,
+                                        initargs=(self.log_queue,))
+        else:
+            # In a thread pool, the child shares our logging setup
+            # (see _assert_logged())
+            self.mp_context = None
+            self.log_queue = None
+            self.executor_kwargs = dict(initializer=init_fail)
+        super().setUp()
+
+    def test_initializer(self):
+        with self._assert_logged('ValueError: error in initializer'):
+            try:
+                future = self.executor.submit(get_init_status)
+            except BrokenExecutor:
+                # Perhaps the executor is already broken
+                pass
+            else:
+                with self.assertRaises(BrokenExecutor):
+                    future.result()
+
+            # At some point, the executor should break
+            for _ in support.sleeping_retry(support.SHORT_TIMEOUT,
+                                            "executor not broken"):
+                if self.executor._broken:
+                    break
+
+            # ... and from this point submit() is guaranteed to fail
+            with self.assertRaises(BrokenExecutor):
+                self.executor.submit(get_init_status)
+
+    @contextlib.contextmanager
+    def _assert_logged(self, msg):
+        if self.log_queue is not None:
+            yield
+            output = []
+            try:
+                while True:
+                    output.append(self.log_queue.get_nowait().getMessage())
+            except queue.Empty:
+                pass
+        else:
+            with self.assertLogs('concurrent.futures', 'CRITICAL') as cm:
+                yield
+            output = cm.output
+        self.assertTrue(any(msg in line for line in output),
+                        output)
+
+
+create_executor_tests(globals(), InitializerMixin)
+create_executor_tests(globals(), FailingInitializerMixin)
+
+
+def setUpModule():
+    setup_module()
+
+
+if __name__ == "__main__":
+    unittest.main()