The load of the current file in test_open_head is fine, but open_de9b3fb438 goes into an OOM even in huge (e.g. 10GB) systemd. This probably needs a proper fix by upstream in regard to the migration modules that load the old code, but until then (since the rest works on s390x) this unblocks the package self-test in Debian & Ubuntu. Patch by Christian Ehrhardt <christian.ehrhardt@canonical.com>. This is Debian bug https://bugs.debian.org/984952 and Ubuntu bug https://bugs.launchpad.net/ubuntu/+source/freecad/+bug/1918474. Been part of the Debian edition of FreeCAD since 2021.