Failing autopkgtest because of X server

[François Mazen <francois@mzf.fr>]

Dear mentors,

I'm trying to add auto-pkg-tests to the flightcrew package with CI on
Salsa repo.

When I launch the flightcrew-gui binary via autopkgtest, I got the
following error on Salsa CI [1]:

"flightcrew-gui: cannot connect to X server"

I suppose the Salsa CI server is headless, but adding xvfb and xauth as
dependency [2] does not change the error.

Could you please help?

Thanks,
François

[1] https://salsa.debian.org/mzf-guest/flightcrew/-/jobs/222482
[2] 
https://salsa.debian.org/mzf-guest/flightcrew/blob/master/debian/tests/control