testing with portage
Gentoo Mono Handbook
https://devmanual.gentoo.org/ebuild-writing/functions/src_test/index.html
RESTRICT="test"
https://devmanual.gentoo.org/ebuild-writing/use-conditional-code/
https://devmanual.gentoo.org/general-concepts/dependencies/
https://devmanual.gentoo.org/ebuild-writing/functions/src_test/index.html