[OPAM] dev-repo url as git branch in opam file

Packaging my software as an opam package i would like to test it in a fork of opam-repository.
Since i am still coding, i did not merge my branch yet in my repositories.
So i try to set the dev-repo url in my opam package as an url on a branch like mentioned here : https://opam.ocaml.org/doc/Manual.html#URLs
Could it work ?
Because when i test it seems that opam is still using the master branch.