At MaestroDev we have been using Puppet 3 for a quite some time now, and one of the main reasons to upgrade from Puppet 2.x was the ability of using Hiera as a data backend for all the variables that customize the different vms. We don’t have a lot of machines but pretty much all of them have some difference so Hiera allows us to have the same manifests and modules apply to all the machines by just using different parameters in each server.

But testing Hiera is not that simple. With rspec-puppet you can test each class by passing parameters, but how can you test a class that calls another class and so on, and at some point there you need to inject a parameter?

Well, this is possible with the hiera-puppet-helper gem you can stub the hiera data backend

source 'https://rubygems.org'

group :rake do
gem 'puppet'
gem 'rspec-puppet'
gem 'hiera-puppet-helper'
gem 'rake'
gem 'puppetlabs_spec_helper'
end

require 'puppetlabs_spec_helper/module_spec_helper'
require 'hiera-puppet-helper/rspec'
require 'hiera'
require 'puppet/indirector/hiera'

# config hiera to work with let(:hiera_data)
def hiera_stub
  config = Hiera::Config.load(hiera_config)
  config[:logger] = 'puppet'
  Hiera.new(:config => config)
end

RSpec.configure do |c|
  c.mock_framework = :rspec

  c.before(:each) do
    Puppet::Indirector::Hiera.stub(:hiera => hiera_stub)
  end

end

And then you can use let(:hiera_data) to inject any parameters automatically into the puppet classes from your rspec tests.

require 'spec_helper'

describe 'mymodule::myclass' do

let(:hiera_data) {{
  'mymodule::myclass::myparam' => 'myvalue'
}}

it { should contain_class('mymodule::myclass').with_myparam('myvalue') }

Check out a full module using hiera-puppet-helper at maestro_nodes.