ERROR: test_network_cli_open_shell (units.plugins.connection.test_network_cli.TestConnectionClass)
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Traceback (most recent call last):
  File "/home/adrian/src/ansible/lib/ansible/plugins/connection/paramiko_ssh.py", line 238, in _connect_uncached
    **sock_kwarg
  File "/home/adrian/.local/lib/python3.5/site-packages/paramiko/client.py", line 361, in connect
    server_key)
  File "/home/adrian/src/ansible/lib/ansible/plugins/connection/paramiko_ssh.py", line 97, in missing_host_key
    self.connection.connection_lock()
  File "/home/adrian/src/ansible/lib/ansible/plugins/connection/__init__.py", line 270, in connection_lock
    display.vvvv('CONNECTION: pid %d waiting for lock on %d' % (os.getpid(), f), host=self._play_context.remote_addr)
TypeError: %d format: a number is required, not NoneType

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/adrian/src/ansible/test/units/plugins/connection/test_network_cli.py", line 75, in test_network_cli_open_shell
    conn.open_shell()
  File "/home/adrian/src/ansible/lib/ansible/plugins/connection/__init__.py", line 52, in wrapped
    self._connect()
  File "/home/adrian/src/ansible/lib/ansible/plugins/connection/network_cli.py", line 63, in _connect
    super(Connection, self)._connect()
  File "/home/adrian/src/ansible/lib/ansible/plugins/connection/paramiko_ssh.py", line 144, in _connect
    self.ssh = SSH_CONNECTION_CACHE[cache_key] = self._connect_uncached()
  File "/home/adrian/src/ansible/lib/ansible/plugins/connection/paramiko_ssh.py", line 249, in _connect_uncached
    raise AnsibleConnectionFailure(msg)
ansible.errors.AnsibleConnectionFailure: %d format: a number is required, not NoneType