diff --git a/mrbgems/mruby-dir/test/dir.rb b/mrbgems/mruby-dir/test/dir.rb
index 7dbb4d3a2..9ddc9661b 100644
--- a/mrbgems/mruby-dir/test/dir.rb
+++ b/mrbgems/mruby-dir/test/dir.rb
@@ -133,5 +133,6 @@ assert('Dir#seek') do
 end
 
 assert('DirTest.teardown') do
+  GC.start
   assert_nothing_raised{DirTest.teardown}
 end