Use Puppet lint and ignore its warnings?
--- /dev/null
+--no-single_quote_string_with_variables-check
group :development, :test do
gem 'rake', :require => false
gem 'rspec-puppet', :require => false
+ gem 'puppet-lint', :require => false
gem 'puppetlabs_spec_helper', :require => false
gem 'serverspec', :require => false
gem 'beaker', :require => false
require 'puppetlabs_spec_helper/rake_tasks'
+require 'puppet-lint/tasks/puppet-lint'
+
+PuppetLint.configuration.send('disable_single_quote_string_with_variables')