What i do is add a hiera config in my spec_helper: https://github.com/voxpupuli/puppet-openproject/blob/b75322a7ae0bd2bd6002e7e90af4ba0c5a1ab837/spec/spec_helper.rb#L15 ; this in itself uses your module's hiera.yaml config. For beaker tsting something similar, i add rspec configs so it takes a acceptance hiera data structure and you can simulate hiera data lookup in this context: https://github.com/voxpupuli/puppet-openprojec