[MODEL] Added auxiliary Rake task for integration tests, run against 3 and 4 gemfiles

With the refactored tests, we have to provide a specific BUNDLE_GEMFILE for integration tests,
so added a wrapper Rake task, which sets it up and runs the auxiliary task.

The interface for the end user stays the same, they just run:

    $ bundle exec rake test:integration

Author: karmi

Rakefile

@@ -69,7 +69,7 @@ namespace :test do
     #
     puts '-'*80
     sh "cd #{__current__.join('elasticsearch-model')} && unset BUNDLE_GEMFILE &&" +
-       %Q| #{ ENV['TEST_BUNDLE_GEMFILE'] ? "BUNDLE_GEMFILE=#{ENV['TEST_BUNDLE_GEMFILE']}" : '' }|  +
+       %Q| #{ ENV['TEST_BUNDLE_GEMFILE'] ? "BUNDLE_GEMFILE='#{ENV['TEST_BUNDLE_GEMFILE']}'" : '' }|  +
        " bundle exec rake test:integration"
     puts "\n"
 

elasticsearch-model/Rakefile

@@ -22,12 +22,18 @@ namespace :test do
     # test.warning = true
   end
 
-  Rake::TestTask.new(:integration) do |test|
+  Rake::TestTask.new(:run_integration) do |test|
     Rake::Task['test:ci_reporter'].invoke if ENV['CI']
     test.libs << 'lib' << 'test'
     test.test_files = FileList["test/integration/**/*_test.rb"]
   end
 
+  desc "Run integration tests against ActiveModel 3 and 4"
+  task :integration do
+    sh "BUNDLE_GEMFILE='#{File.expand_path('../gemfiles/3.0.gemfile', __FILE__)}' bundle exec rake test:run_integration"
+    sh "BUNDLE_GEMFILE='#{File.expand_path('../gemfiles/4.0.gemfile', __FILE__)}' bundle exec rake test:run_integration"
+  end
+
   Rake::TestTask.new(:all) do |test|
     Rake::Task['test:ci_reporter'].invoke if ENV['CI']
     test.libs << 'lib' << 'test'