diff --git a/lib/rubygems/test_case.rb b/lib/rubygems/test_case.rb
index 39aa4fc9a7..bb6f4fde88 100644
--- a/lib/rubygems/test_case.rb
+++ b/lib/rubygems/test_case.rb
@@ -756,6 +756,9 @@ class Gem::TestCase < MiniTest::Unit::TestCase
     old_loaded_features = $LOADED_FEATURES.dup
     yield
   ensure
+    prefix = File.dirname(__FILE__) + "/"
+    new_features = ($LOADED_FEATURES - old_loaded_features)
+    old_loaded_features.concat(new_features.select {|f| f.rindex(prefix, 0)})
     $LOADED_FEATURES.replace old_loaded_features
   end