Puppet rspec testing with automatic hiera lookups (implicit hiera lookup like puppet 3.x)

This article is an add-on to my other article regarding puppet & rspec.
This article only covers automatic hiera lookups used during rspec puppet runs.
Many thanks to Jan (janwaech<at>gmail<dot>com) who spend the time digging into rspec-puppet code finding this nice solution.

Puppet rspec testing and hiera

Rspec testing your puppet modules supports you in having stable and functional modules.
For a couple of weeks there is hiera integration in rspec-puppet.