(maint) Test against specific, supported versions of Puppet

.travis.yml

@@ -1,18 +1,45 @@
+---
 language: ruby
+
 sudo: false
+
 bundler_args: --without development acceptance
-script:
-  - "bundle exec rake $CHECK"
+
 notifications:
   email: false
+
 rvm:
   - 1.9.3
   - 2.0.0
   - 2.1.0
+  - 2.3.1
 
 env:
-  - "CHECK=spec SPEC_OPTS='--color --format documentation'"
-  - "CHECK=rubocop"
+  matrix:
+    - PUPPET_GEM_VERSION="~> 3.7.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 3.8.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 3" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4.0.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4.1.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4.2.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4.3.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4.4.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4.5.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4.6.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4.7.0" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4" CHECK=spec
+    - PUPPET_GEM_VERSION="~> 4" CHECK=rubocop
+
+script: 'SPEC_OPTS="--format documentation" bundle exec rake $CHECK'
 
 matrix:
   fast_finish: true
+  exclude:
+    - rvm: 1.9.3
+      env: PUPPET_GEM_VERSION="~> 4" CHECK=rubocop
+    - rvm: 2.3.1
+      env: PUPPET_GEM_VERSION="~> 3.7.0" CHECK=spec
+    - rvm: 2.3.1
+      env: PUPPET_GEM_VERSION="~> 3.8.0" CHECK=spec
+    - rvm: 2.3.1
+      env: PUPPET_GEM_VERSION="~> 3" CHECK=spec

Gemfile

@@ -6,12 +6,10 @@ gem 'rgen'
 gem 'redcarpet'
 gem 'yard', '~> 0.9.5'
 
-puppetversion = ENV['PUPPET_VERSION']
-
-if puppetversion
-  gem 'puppet', puppetversion
+if ENV['PUPPET_GEM_VERSION']
+  gem 'puppet', ENV['PUPPET_GEM_VERSION'], :require => false
 else
-  gem 'puppet'
+  gem 'puppet', :require => false
 end
 
 group :test do
@@ -19,7 +17,6 @@ group :test do
   gem 'mocha'
   gem 'puppetlabs_spec_helper'
   gem 'serverspec'
-  gem 'rubocop', '~> 0.41.0'
 end
 
 group :acceptance do
@@ -36,3 +33,7 @@ group :development do
     gem 'pry-byebug'
   end
 end
+
+gem 'json',      '<= 1.8'   if RUBY_VERSION < '2.0.0'
+gem 'json_pure', '<= 2.0.1' if RUBY_VERSION < '2.0.0'
+gem 'rubocop'               if RUBY_VERSION >= '2.0.0'