Use system libraries with dune runtest

Is there a way to let dune runtest --verbose --for-release-of-packages=gen ignore the workspace and use system libraries for dependencies it would otherwise try to satisfy by compiling them from scratch?

ocaml-gen.git#src/dune
(test
 (name inline_test)
 (modules inline_test)
 (libraries gen oUnit qcheck))

In this example it is supposed to use gen from the equivalent of the ocamlfind query gen result, instead of using the (library (name gen)) rule a few lines above.

That’s not possible. Local libraries always shadow external ones.