allow for specifying a build pattern when executing parallel specs

Change-Id: Ia855d75d03f8c34b4e0968b519a8d66eaf184b92
Reviewed-on: https://gerrit.instructure.com/9569
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Jake Sorce <jake@instructure.com>

lib/tasks/rspec.rake

@@ -208,5 +208,18 @@ namespace :parallel do
     test_files.map! { |f| "#{Rails.root}/#{f}" }
     Rake::Task['parallel:spec'].invoke(count, '', '', test_files.join(' '))
   end
+
+  task :pattern, :count, :file_pattern do |t, args|
+    require "parallel_tests"
+    count = args[:count]
+    file_pattern = args[:file_pattern]
+    if count.nil? || file_pattern.nil?
+      raise "Must specify a thread count and file pattern"
+    end
+    test_files = FileList[file_pattern]
+    test_files.map! { |f| "#{Rails.root}/#{f}" }
+    Rake::Task['parallel:spec'].invoke(count, '', '', test_files.join(' '))
+  end
 end
+
 end