The assumption here seems to be that it's an overlay onto the
current environment which would make sense; but the implementation in
gnome-desktop-testing currently removes all other environment variables
(see GNOME/gnome-desktop-testing#1). This causes test failure when the
tests are run in Debian's autopkgtest framework, possibly because PATH
is cleared.
Signed-off-by: Simon McVittie <smcv@debian.org>
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2009>