What Linux Distro to choose for beta release testing?

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Hi to all!

I'm already testing issues for beta/alpha releases, running in Windows 10/7.

But I want to cross-test those issues in Linux. (Running it in VirtualBox) I would like it to be easy - just a click or a command - to get the latest release.

(Of course those distribution only have a stable release in their own software repository!)

Regards,

Mike