Setting this to default to an empty Hash makes https://github.com/anodelman/puppet-acceptance/blob/fae27a2d7600c0b5c292a6cc3b6b554ab0b2e8ea/lib/puppet_acceptance/command.rb#L88 unnecessary. Though it looks like this https://github.com/anodelman/puppet-acceptance/blob/fae27a2d7600c0b5c292a6cc3b6b554ab0b2e8ea/lib/puppet_acceptance/command.rb#L154 has already made that line unnecessary.