This problem may affect workflows that integrate tools that require an available display (as in real or virtual screen).
During testing, some of these tools are run and will require the display. When no physical display is attached (which is done just checking the value of the
$DISPLAY environment variable) then nipype tries to create a virtual display with that tool,
Xvfb. This fails for OSX because
Xvfb needs to be run as root.
However, in your setting this should not happen since you have a value for your
Try setting the the display variable via nipype options. You can create a file
$HOME/nipype.cfg with the following content:
display_variable = :0
then, make sure the
$DISPLAY variable is not set (
unset $DISPLAY), and finally check if tests run correctly.
Please let us know if that resolved the issue.