1 files changed, 6 insertions, 5 deletions
diff --git a/actionpack/test/controller/send_file_test.rb b/actionpack/test/controller/send_file_test.rb
index 4df2f8b98d..2c833aa2e5 100644
--- a/actionpack/test/controller/send_file_test.rb
+++ b/actionpack/test/controller/send_file_test.rb
@@ -30,17 +30,20 @@ class SendFileWithActionControllerLive < SendFileController
 end
 
 class SendFileTest < ActionController::TestCase
-  tests SendFileController
   include TestFileUtils
 
-  Mime::Type.register "image/png", :png unless defined? Mime::PNG
-
   def setup
+    @mime_type_defined = defined? Mime::PNG
+    Mime::Type.register "image/png", :png unless @mime_type_defined
     @controller = SendFileController.new
     @request = ActionController::TestRequest.new
     @response = ActionController::TestResponse.new
   end
 
+  teardown do
+    Mime::Type.unregister :png unless @mime_type_defined
+  end
+
   def test_file_nostream
     @controller.options = { :stream => false }
     response = nil
@@ -201,8 +204,6 @@ class SendFileTest < ActionController::TestCase
     end
   end
 
-  tests SendFileWithActionControllerLive
-
   def test_send_file_with_action_controller_live
     @controller = SendFileWithActionControllerLive.new
     @controller.options = { :content_type => "application/x-ruby" }