Pablo wrote on the buildbot-status mailing list:
"It seems that this worker has some bad upgrade to SSL as all branches fail at the same time:"

AMD64 Debian root 3.7:
https://buildbot.python.org/all/#builders/3/builds/8

======================================================================
ERROR: test_sock_sendfile_exception (test.test_asyncio.test_unix_events.SelectorEventLoopUnixSockSendfileTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 613, in test_sock_sendfile_exception
    sock, proto = self.prepare()
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 491, in prepare
    self.run_loop(self.loop.sock_connect(sock, (support.HOST, port)))
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 481, in run_loop
    return self.loop.run_until_complete(coro)
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/asyncio/base_events.py", line 579, in run_until_complete
    return future.result()
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/asyncio/selector_events.py", line 460, in sock_connect
    if isinstance(sock, ssl.SSLSocket):
AttributeError: 'NoneType' object has no attribute 'SSLSocket'
======================================================================
ERROR: test_sock_sendfile_iobuffer (test.test_asyncio.test_unix_events.SelectorEventLoopUnixSockSendfileTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 524, in test_sock_sendfile_iobuffer
    sock, proto = self.prepare()
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 491, in prepare
    self.run_loop(self.loop.sock_connect(sock, (support.HOST, port)))
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 481, in run_loop
    return self.loop.run_until_complete(coro)
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/asyncio/base_events.py", line 579, in run_until_complete
    return future.result()
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/asyncio/selector_events.py", line 460, in sock_connect
    if isinstance(sock, ssl.SSLSocket):
AttributeError: 'NoneType' object has no attribute 'SSLSocket'
======================================================================
ERROR: test_sock_sendfile_not_a_file (test.test_asyncio.test_unix_events.SelectorEventLoopUnixSockSendfileTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 515, in test_sock_sendfile_not_a_file
    sock, proto = self.prepare()
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 491, in prepare
    self.run_loop(self.loop.sock_connect(sock, (support.HOST, port)))
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/test/test_asyncio/test_unix_events.py", line 481, in run_loop
    return self.loop.run_until_complete(coro)
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/asyncio/base_events.py", line 579, in run_until_complete
    return future.result()
  File "/root/buildarea/3.7.angelico-debian-amd64/build/Lib/asyncio/selector_events.py", line 460, in sock_connect
    if isinstance(sock, ssl.SSLSocket):
AttributeError: 'NoneType' object has no attribute 'SSLSocket'