Require at least one value in diff-root and meta-diff arguments
Require at least one value in diff-root
and meta-diff
arguments. None of the changed ones make sense to be passed without any value.
Not sure how to extensively test this so I'll just add full-unit-tests to make me feel better
/cc @jchapman @nstyles @jcatmore @tsulaia @amete @tcuhadar @simmons