Make the BackdoorServer kill its spawned greenlets when it is stopped.

Hopefully this will help diagnose the timeout error seen (only) on
Appveyor: The test that runs after test_multi hangs; all the other tests
work. (This was verified by changing the name of test_multi and thus its
sort order; the test after it is the one that fails.)

changelog.rst

@@ -141,8 +141,11 @@ Other Changes
   each other. **Note:** Writing to the *io* property of a FileObject should be
   considered deprecated.
 - Timeout exceptions (and other asynchronous exceptions) could cause
-  the Backdoor server to fail to properly manage the
-  stdout/stderr/stdin values. Reported with a patch in :pr:`874` by stefanmh.
+  the BackdoorServer to fail to properly manage the
+  stdout/stderr/stdin values. Reported with a patch in :pr:`874` by
+  stefanmh.
+- The BackDoorServer now tracks spawned greenlets (connections) and
+  kills them in its ``stop`` method.
 
 Servers
 ~~~~~~~

src/gevent/backdoor.py

@@ -16,6 +16,7 @@ from code import InteractiveConsole
 from gevent.greenlet import Greenlet
 from gevent.hub import getcurrent
 from gevent.server import StreamServer
+from gevent.pool import Pool
 
 __all__ = ['BackdoorServer']
 
@@ -88,6 +89,10 @@ class BackdoorServer(StreamServer):
         Hello from gevent backdoor!
         >> print(foo)
         From defined scope!
+
+    .. versionchanged:: 1.2a1
+       Spawned greenlets are now tracked in a pool and killed when the server
+       is stopped.
     """
 
     def __init__(self, listener, locals=None, banner=None, **server_args):
@@ -96,7 +101,8 @@ class BackdoorServer(StreamServer):
             at the top-level.
         :keyword banner: If geven, a string that will be printed to each connecting user.
         """
-        StreamServer.__init__(self, listener, spawn=_Greenlet_stdreplace.spawn, **server_args)
+        group = Pool(greenlet_class=_Greenlet_stdreplace) # no limit on number
+        StreamServer.__init__(self, listener, spawn=group, **server_args)
         _locals = {'__doc__': None, '__name__': '__console__'}
         if locals:
             _locals.update(locals)

src/greentest/test__backdoor.py

+from __future__ import print_function
 import greentest
 import gevent
 from gevent import socket
 from gevent import backdoor
-from _six import xrange
-
 
 def read_until(conn, postfix):
     read = b''
@@ -30,6 +29,7 @@ class Test(greentest.TestCase):
     def tearDown(self):
         self._server.stop()
         self._server = None
+        gevent.sleep() # let spawned greenlets die
         super(Test, self).tearDown()
 
     def _make_server(self, *args, **kwargs):
@@ -48,25 +48,29 @@ class Test(greentest.TestCase):
         line = readline(conn)
         self.assertEqual(line, '')
         conn.close()
+        self.close_on_teardown.remove(conn)
 
     def test_multi(self):
         self._make_server()
 
         def connect():
             conn = self._create_connection()
-            read_until(conn, '>>> ')
+            read_until(conn, b'>>> ')
             conn.sendall(b'2+2\r\n')
             line = readline(conn)
             self.assertEqual(line.strip(), '4', repr(line))
             self._close(conn)
 
-        jobs = [gevent.spawn(connect) for _ in xrange(10)]
-        gevent.joinall(jobs, raise_error=True)
+        jobs = [gevent.spawn(connect) for _ in range(10)]
+        done = gevent.joinall(jobs, raise_error=True)
+
+        self.assertEqual(len(done), len(jobs), done)
+
 
     def test_quit(self):
         self._make_server()
         conn = self._create_connection()
-        read_until(conn, '>>> ')
+        read_until(conn, b'>>> ')
         self._close(conn)
 
     def test_sys_exit(self):