Add rubocop

.rubocop.yml

+require: rubocop-rspec
+AllCops:
+  TargetRubyVersion: 1.9
+  Include:
+    - ./**/*.rb
+  Exclude:
+    - vendor/**/*
+    - .vendor/**/*
+    - pkg/**/*
+    - spec/fixtures/**/*
+
+# We don't use rspec in this way
+RSpec/DescribeClass:
+  Enabled: False
+
+RSpec/ImplicitExpect:
+  Enabled: False
+
+# Example length is not necessarily an indicator of code quality
+RSpec/ExampleLength:
+  Enabled: False
+
+RSpec/NamedSubject:
+  Enabled: False

Gemfile

 source 'https://rubygems.org'
 
 gem 'puppet', ENV.key?('PUPPET_VERSION') ? "~> #{ENV['PUPPET_VERSION']}" : '>= 2.7'
-gem 'rspec-puppet', '~> 2.0'
+gem 'rspec-puppet', '>= 2.0'
 gem 'puppetlabs_spec_helper', '>= 0.1.0'
 gem 'puppet-lint', '>= 1'
 gem 'facter', '>= 1.7.0'
 gem 'rspec-puppet-facts', :require => false
 
 gem 'puppet-lint-strict_indent-check'
+gem 'puppet-lint-absolute_classname-check'
+gem 'puppet-lint-leading_zero-check'
+gem 'puppet-lint-trailing_comma-check'
+gem 'puppet-lint-version_comparison-check'
+gem 'puppet-lint-classes_and_types_beginning_with_digits-check'
+gem 'puppet-lint-unquoted_string-check'
+gem 'puppet-lint-variable_contains_upcase'
+
+gem 'metadata-json-lint'
+
+gem 'rubocop-rspec', '~> 1.6', :require => false if RUBY_VERSION >= '2.3.0'

Rakefile

@@ -2,12 +2,10 @@ require 'rubygems'
 require 'puppetlabs_spec_helper/rake_tasks'
 require 'puppet-lint/tasks/puppet-lint'
 
-if not ENV['SPEC_OPTS']
-  ENV['SPEC_OPTS'] = '--format documentation'
-end
+ENV['SPEC_OPTS'] = '--format documentation' unless ENV['SPEC_OPTS']
 
-PuppetSyntax.exclude_paths = [ "vendor/**/*.*" ]
-PuppetLint.configuration.ignore_paths = ["spec/**/*.pp", "pkg/**/*.pp", "vendor/**/*.pp"]
+PuppetSyntax.exclude_paths            = ['vendor/**/*.*']
+PuppetLint.configuration.ignore_paths = %w(spec/**/*.pp pkg/**/*.pp vendor/**/*.pp)
 
 # Alternative configuration until https://github.com/rodjek/puppet-lint/pull/397 gets merged
 Rake::Task[:lint].clear
@@ -15,4 +13,4 @@ PuppetLint::RakeTask.new :lint do |config|
   config.ignore_paths = PuppetLint.configuration.ignore_paths
 end
 
-task :all => [ :validate, :lint, :spec ]
+task :all => [:validate, :lint, :spec, :rubocop]