Example:
~/chromiumos/src/third_party/autotest/files/frontend/afe$ ./rpc_interface_unittest.py 

<snip>

  File "/usr/lib/python2.7/httplib.py", line 1013, in endheaders
    self._send_output(message_body)
  File "/usr/lib/python2.7/httplib.py", line 864, in _send_output
    self.send(msg)
  File "/usr/lib/python2.7/httplib.py", line 826, in send
    self.connect()
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/connection.py", line 141, in connect
    conn = self._new_conn()
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/connection.py", line 120, in _new_conn
    (self.host, self.port), self.timeout, **extra_kw)
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/util/connection.py", line 85, in create_connection
    raise err
ProtocolError: ('Connection aborted.', error(110, 'Connection timed out'))
DEBUG:elasticsearch:> {"time_recorded": 1490246895.047299, "changed_by": "autotest_system", "hostname": "host9", "locked": true, "lock_reason": "Testing forward to shard"}
DEBUG:urllib3.util.retry:Converted retries value: False -> Retry(total=False, connect=None, read=None, redirect=0)
INFO:urllib3.connectionpool:Starting new HTTP connection (4): 172.25.65.90
WARNING:elasticsearch:POST http://172.25.65.90:9200/cautotest/lock_history [status:N/A request:15.023s]
Traceback (most recent call last):
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/elasticsearch/connection/http_urllib3.py", line 74, in perform_request
    response = self.pool.urlopen(method, url, body, retries=False, headers=self.headers, **kw)
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/connectionpool.py", line 559, in urlopen
    _pool=self, _stacktrace=stacktrace)
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/util/retry.py", line 223, in increment
    raise six.reraise(type(error), error, _stacktrace)
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/connectionpool.py", line 516, in urlopen
    body=body, headers=headers)
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/connectionpool.py", line 308, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "/usr/lib/python2.7/httplib.py", line 1017, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib/python2.7/httplib.py", line 1051, in _send_request
    self.endheaders(body)
  File "/usr/lib/python2.7/httplib.py", line 1013, in endheaders
    self._send_output(message_body)
  File "/usr/lib/python2.7/httplib.py", line 864, in _send_output
    self.send(msg)
  File "/usr/lib/python2.7/httplib.py", line 826, in send
    self.connect()
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/connection.py", line 141, in connect
    conn = self._new_conn()
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/connection.py", line 120, in _new_conn
    (self.host, self.port), self.timeout, **extra_kw)
  File "/usr/local/google/home/akeshet/chromiumos/src/third_party/autotest/files/site-packages/urllib3/util/connection.py", line 85, in create_connection
    raise err
ProtocolError: ('Connection aborted.', error(110, 'Connection timed out'))
DEBUG:elasticsearch:> {"time_recorded": 1490246895.047299, "changed_by": "autotest_system", "hostname": "host9", "locked": true, "lock_reason": "Testing forward to shard"}
ERROR:root:ConnectionError(('Connection aborted.', error(110, 'Connection timed out'))) caused by: ProtocolError(('Connection aborted.', error(110, 'Connection timed out')))
.........
----------------------------------------------------------------------
Ran 51 tests in 681.206s

Most of the time looks to me like it is spent in retry loops on elasticsearch metrics, which a unittest really shouldn't even be sending.