Add some tests

Lib/test/test_concurrent_futures/test_process_pool.py

@@ -1,8 +1,11 @@
+import multiprocessing
 import os
+import queue
 import sys
 import threading
 import time
 import unittest
+import unittest.mock
 from concurrent import futures
 from concurrent.futures.process import BrokenProcessPool
 
@@ -22,6 +25,12 @@ def __init__(self, mgr):
     def __del__(self):
         self.event.set()
 
+def _put_sleep_put(queue):
+    """ Used as part of test_process_pool_executor_terminate_workers """
+    queue.put('started')
+    time.sleep(2)
+    queue.put('finished')
+
 
 class ProcessPoolExecutorTest(ExecutorTest):
 
@@ -218,6 +227,60 @@ def mock_start_new_thread(func, *args, **kwargs):
                     list(executor.map(mul, [(2, 3)] * 10))
             executor.shutdown()
 
+    def test_process_pool_executor_terminate_workers(self):
+        manager = multiprocessing.Manager()
+        q = manager.Queue()
+
+        with futures.ProcessPoolExecutor(max_workers=1) as executor:
+            executor.submit(_put_sleep_put, q)
+
+            # We should get started, but not finished since we'll terminate the workers just after
+            self.assertEqual(q.get(timeout=1), 'started')
+
+            executor.terminate_workers()
+
+            try:
+                q.get(timeout=1)
+                raise RuntimeError("Queue should not have gotten a second value")
+            except queue.Empty:
+                pass
+
+    def test_process_pool_executor_terminate_workers_dead_workers(self):
+        with futures.ProcessPoolExecutor(max_workers=1) as executor:
+            try:
+                executor.submit(os._exit, 1).result()
+            except BrokenProcessPool:
+                # BrokenProcessPool will be raised by our call to .result() since the worker will die
+                pass
+
+            # The worker has been killed already, terminate_workers should basically no-op
+            executor.terminate_workers()
+
+    def test_process_pool_executor_terminate_workers_not_started_yet(self):
+        with futures.ProcessPoolExecutor(max_workers=1) as executor:
+            # The worker has not been started yet, terminate_workers should basically no-op
+            executor.terminate_workers()
+
+    def test_process_pool_executor_terminate_workers_stops_pool(self):
+        with futures.ProcessPoolExecutor(max_workers=1) as executor:
+            executor.submit(time.sleep, 0).result()
+
+            executor.terminate_workers()
+
+            try:
+                executor.submit(time.sleep, 0).result()
+                raise RuntimeError("Should have raised BrokenProcessPool")
+            except BrokenProcessPool:
+                pass
+
+    @unittest.mock.patch('concurrent.futures.process.os.kill')
+    def test_process_pool_executor_terminate_workers_passes_signal(self, mock_kill):
+        with futures.ProcessPoolExecutor(max_workers=1) as executor:
+            executor.submit(time.sleep, 0).result()
+
+            executor.terminate_workers(9)
+            mock_kill.assert_called_once_with(list(executor._processes.values())[0].pid, 9)
+
 
 create_executor_tests(globals(), ProcessPoolExecutorTest,
                       executor_mixins=(ProcessPoolForkMixin,