*PDK results:* Functionality wise tests passed. The only problem is that PDK is compatible with Ruby 2.1.9 and Facter4 is compatible with Ruby 2.3 and up. At the moment the only syntax change that we've found is that we use _var_name&._ that is used to suppress Nil Class exceptions.
For this there are two solutions: 1. Replace *&.* to be compatible with ruby 2.1.9 2. Implement a backport option for ruby 2.1.9 that allows using the safe navigation operator.