Revert "fix connection backlog offset - updated tests - added tests for 0 and 1"

This reverts commit 2c603b9.

Author: ChristianHrs

Lib/asyncio/selector_events.py

@@ -173,7 +173,7 @@ def _accept_connection(
         # listening socket has triggered an EVENT_READ. There may be multiple
         # connections waiting for an .accept() so it is called in a loop.
         # See https://bugs.python.org/issue27906 for more details.
-        for _ in range(backlog + 1):
+        for _ in range(backlog):
             try:
                 conn, addr = sock.accept()
                 if self._debug:

Lib/test/test_asyncio/test_selector_events.py

@@ -347,18 +347,6 @@ def test_process_events_write_cancelled(self):
               selectors.EVENT_WRITE)])
         self.loop._remove_writer.assert_called_with(1)
 
-    def test_accept_connection_zero_one(self):
-        for backlog in [0, 1]:
-            sock = mock.Mock()
-            sock.accept.return_value = (mock.Mock(), mock.Mock())
-            with self.subTest(backlog):
-                mock_obj = mock.patch.object
-                with mock_obj(self.loop, '_accept_connection2') as accept2_mock:
-                    self.loop._accept_connection(
-                        mock.Mock(), sock, backlog=backlog)
-                self.loop.run_until_complete(asyncio.sleep(0))
-                self.assertEqual(sock.accept.call_count, backlog + 1)
-
     def test_accept_connection_multiple(self):
         sock = mock.Mock()
         sock.accept.return_value = (mock.Mock(), mock.Mock())
@@ -374,7 +362,7 @@ def test_accept_connection_multiple(self):
             self.loop._accept_connection(
                 mock.Mock(), sock, backlog=backlog)
         self.loop.run_until_complete(asyncio.sleep(0))
-        self.assertEqual(sock.accept.call_count, backlog + 1)
+        self.assertEqual(sock.accept.call_count, backlog)
 
     def test_accept_connection_skip_connectionabortederror(self):
         sock = mock.Mock()
@@ -400,7 +388,7 @@ def mock_sock_accept():
         # as in test_accept_connection_multiple avoid task pending
         # warnings by using asyncio.sleep(0)
         self.loop.run_until_complete(asyncio.sleep(0))
-        self.assertEqual(sock.accept.call_count, backlog + 1)
+        self.assertEqual(sock.accept.call_count, backlog)
 
 class SelectorTransportTests(test_utils.TestCase):