IIRC installing memtest86+ was enough in order to have it as a boot option in GRUB2. However today I installed it on this Leap 15 system and it doesn't show up after reboot. At the same time I see:

# ls -l /boot/memtest.bin
-rw-r--r-- 1 root root 182704 Feb 19  2018 /boot/memtest.bin
which is strange (considering the date)

So how can I have memtest86+ as boot entry?