PYTHON-2334 Add regression test for gevent.Timeout compatibility (#475)

Use with statement in Semaphore.release.

pymongo/thread_util.py

@@ -60,10 +60,9 @@ def acquire(self, blocking=True, timeout=None):
     __enter__ = acquire
 
     def release(self):
-        self._cond.acquire()
-        self._value = self._value + 1
-        self._cond.notify()
-        self._cond.release()
+        with self._cond:
+            self._value = self._value + 1
+            self._cond.notify()
 
     def __exit__(self, t, v, tb):
         self.release()

test/test_client.py

@@ -1944,6 +1944,36 @@ def poller():
         task.kill()
         self.assertTrue(task.dead)
 
+    def test_gevent_timeout(self):
+        if not gevent_monkey_patched():
+            raise SkipTest("Must be running monkey patched by gevent")
+        from gevent import spawn, Timeout
+        client = rs_or_single_client(maxPoolSize=1)
+        coll = client.pymongo_test.test
+        coll.insert_one({})
+
+        def contentious_task():
+            # The 10 second timeout causes this test to fail without blocking
+            # forever if a bug like PYTHON-2334 is reintroduced.
+            with Timeout(10):
+                coll.find_one({'$where': delay(1)})
+
+        def timeout_task():
+            with Timeout(.5):
+                try:
+                    coll.find_one({})
+                except Timeout:
+                    pass
+
+        ct = spawn(contentious_task)
+        tt = spawn(timeout_task)
+        tt.join(15)
+        ct.join(15)
+        self.assertTrue(tt.dead)
+        self.assertTrue(ct.dead)
+        self.assertIsNone(tt.get())
+        self.assertIsNone(ct.get())
+
 
 if __name__ == "__main__":
     unittest.main()