booting a custom linux kernel
 

I followed a tutorial and compiled a custom linux kernel on fedora 22. How to boot it? is virtualisation necessary for faster code-compile-test cycles ?

Stick an entry in your boot-loader - for Fedora that would be /boot/grub2/grub.cfg.

Best to use a similar name to Fedora (add a unique suffix) so os-prober will find it and add the entry for you when mkconfig is run.
I run real systems rather than virtual - personal choice.

thank you very much