Using Lupin to test alpha/beta ubuntu installations

[noorez]

I had the thought of testing ubuntu versions still in alpha/beta using the Lupin functionality. Now, I know Lubi can accomplish this but it looks like it hasn't been maintained in like forever and also Lupin functionality looks like it has been merged into mainline ubuntu already. How can I manually get Lupin stuff configured?

It seems like I could use the following: https://help.ubuntu.com/community/Grub2/ISOBoot#Booting_without_a_GRUB_Menuentry but then I wouldn't know how to target and then boot a loopmounted device.

Any advice/help on this?

[noorez]

bump

If I create a disk image on my hard disk (e.g. /internal/test.img), during installation, how can I loop mount that 'device' in order to install ubuntu to it. After it is installed, I would need to be able to create an entry in grub to boot from it...