✘ daniel@daniels-ubuntu  ~/gnome-software-tests  bzr@565  ubuntu-system-tests build-qemu --iso "/home/daniel/Downloads/ubuntu-17.10-desktop-amd64 (1).iso" --img /home/daniel/dev -s         
In silent mode no default value specified for option: "output_dir". Continuing with value unset.
In silent mode no default value specified for option: "wifi_ssid". Continuing with value unset.
In silent mode no default value specified for option: "wifi_password". Continuing with value unset.
In silent mode no default value specified for option: "_twilio_account_sid". Continuing with value unset.
In silent mode no default value specified for option: "_twilio_auth_token". Continuing with value unset.
In silent mode no default value specified for option: "password_outlook". Continuing with value unset.
In silent mode no default value specified for option: "password_yahoo". Continuing with value unset.
In silent mode no default value specified for option: "password_imap". Continuing with value unset.
Traceback (most recent call last):
  File "/usr/bin/ubuntu-system-tests", line 11, in <module>
    load_entry_point('ubuntu-system-tests==1.0', 'console_scripts', 'ubuntu-system-tests')()
  File "/usr/lib/python3/dist-packages/ubuntu_system_tests/run.py", line 27, in main
    return command_line.main(argv)
  File "/usr/lib/python3/dist-packages/ubuntu_system_tests/host/command_line.py", line 260, in main
    return build_qemu(args)
  File "/usr/lib/python3/dist-packages/ubuntu_system_tests/host/command_line.py", line 430, in build_qemu
    clean_output_directory(config_stack)
  File "/usr/lib/python3/dist-packages/ubuntu_system_tests/host/command_line.py", line 622, in clean_output_directory
    path = os.path.abspath(config_stack.get('output_dir'))
  File "/usr/lib/python3.6/posixpath.py", line 369, in abspath
    path = os.fspath(path)
TypeError: expected str, bytes or os.PathLike object, not NoneType