Add env var for puppet package name

This is useful for someone who has their own
package and wants to test with that

README.md

@@ -46,6 +46,7 @@ Other common environment variables:
 * `BEAKER_PROVISION` can be set to `no` to reuse a box. Note that the box must exist already. See `BEAKER_DESTROY`
 * `BEAKER_SETFILE` is used to point to a setfile containing definitions. To avoid storing large YAML files in all repositories, [beaker-hostgenerator](https://github.com/voxpupuli/beaker-hostgenerator) is used to generate them on the fly when the file is not present.
 * `BEAKER_PUPPET_COLLECTION` defines the puppet collection that will be configured, defaults to `puppet`. When set to `none`, no repository will be configured and distro package naming is assumed. When set to `preinstalled`, it assumes the OS is already set up with a collection but it still ensures `puppet-agent` is installed.
+* `BEAKER_PUPPET_PACKAGE_NAME` optional env var to set the puppet agent package name. If not set, the package name will be searched in [puppet_metadata](https://github.com/voxpupuli/puppet_metadata#puppet_metadata).
 
 Since it's still plain [RSpec](https://rspec.info/), it is also possible to call an individual test file:
 

lib/voxpupuli/acceptance/spec_helper_acceptance.rb

@@ -18,7 +18,7 @@ def configure_beaker(modules: :metadata, &block)
       unless %w[none preinstalled].include?(collection)
         BeakerPuppetHelpers::InstallUtils.install_puppet_release_repo_on(host, collection)
       end
-      package_name = BeakerPuppetHelpers::InstallUtils.puppet_package_name(host, prefer_aio: collection != 'none')
+      package_name = ENV.fetch('BEAKER_PUPPET_PACKAGE_NAME', BeakerPuppetHelpers::InstallUtils.puppet_package_name(host, prefer_aio: collection != 'none'))
       host.install_package(package_name)
 
       # by default, puppet-agent creates /etc/profile.d/puppet-agent.sh which adds /opt/puppetlabs/bin to PATH