++ mktemp -d
+ checkout=/tmp/tmp.bCftxNWIK2
+ trap 'rm -rf "$checkout"' EXIT
+ cp -R /var/lib/ci-tron/sources/6dc74fae8afe15c8/. /tmp/tmp.bCftxNWIK2
+ cd /tmp/tmp.bCftxNWIK2
+ nix develop --command python3 scripts/headless_test.py
GC Warning: Could not open /proc/stat
headless_test: FAIL: XDG_RUNTIME_DIR is unset — not a Wayland-capable session
+ rm -rf /tmp/tmp.bCftxNWIK2