2 files changed, 70 insertions, 0 deletions
diff --git a/railties/lib/rails/test_unit/sub_test_task.rb b/railties/lib/rails/test_unit/sub_test_task.rb
index 36657dbdd4..ac2bde2071 100644
--- a/railties/lib/rails/test_unit/sub_test_task.rb
+++ b/railties/lib/rails/test_unit/sub_test_task.rb
@@ -2,6 +2,41 @@ require 'rake/testtask'
 
 module Rails
   class TestTask < Rake::TestTask # :nodoc: all
+    class TestInfo
+      def initialize(tasks)
+        @tasks = tasks
+      end
+
+      def files
+        @tasks.find_all { |t| File.file?(t) && !File.directory?(t) }
+      end
+
+      def tasks
+        @tasks - files - opt_names
+      end
+
+      def opts
+        opts = opt_names
+        if opts.any?
+          "-n #{opts.join ' '}"
+        end
+      end
+
+      private
+
+      def opt_names
+        (@tasks - files).reject { |t| task_defined? t }
+      end
+
+      def task_defined?(task)
+        Rake::Task.task_defined? task
+      end
+    end
+
+    def self.test_info(tasks)
+      TestInfo.new tasks
+    end
+
     def initialize(name = :test)
       super
       @libs << "test" # lib *and* test seem like a better default
diff --git a/railties/test/test_info_test.rb b/railties/test/test_info_test.rb
new file mode 100644
index 0000000000..2f78dcff1b
--- /dev/null
+++ b/railties/test/test_info_test.rb
@@ -0,0 +1,35 @@
+require 'abstract_unit'
+require 'rails/test_unit/sub_test_task'
+
+module Rails
+  class TestInfoTest < ActiveSupport::TestCase
+    def test_test_files
+      info = new_test_info ['test']
+      assert_predicate info.files, :empty?
+      assert_nil info.opts
+      assert_equal ['test'], info.tasks
+    end
+
+    def test_with_file
+      info = new_test_info ['test', __FILE__]
+      assert_equal [__FILE__], info.files
+      assert_nil info.opts
+      assert_equal ['test'], info.tasks
+    end
+
+    def test_with_opts
+      info = new_test_info ['test', __FILE__, '/foo/']
+      assert_equal [__FILE__], info.files
+      assert_equal '-n /foo/', info.opts
+      assert_equal ['test'], info.tasks
+    end
+
+    def new_test_info(tasks)
+      Class.new(TestTask::TestInfo) {
+        def task_defined?(task)
+          task == "test"
+        end
+      }.new tasks
+    end
+  end
+end