diff --git a/test/runner.rb b/test/runner.rb
index 63503e4165..3a8eb78add 100644
--- a/test/runner.rb
+++ b/test/runner.rb
@@ -21,7 +21,7 @@ module Test::Unit
   module ZombieHunter
 
     def before_setup
-      @@tracepoint_captured_stat = TracePoint.stat.map{|k, (activated, deleted)| [k, activated]}
+      @tracepoint_captured_stat = TracePoint.stat.map{|k, (activated, deleted)| [k, activated]}
     end
 
     def after_teardown
@@ -30,7 +30,7 @@ module Test::Unit
 
       # detect zombie traces.
       assert_equal(
-        @@tracepoint_captured_stat,
+        @tracepoint_captured_stat,
         TracePoint.stat.map{|k, (activated, deleted)| [k, activated]},
         "The number of active trace events was changed"
       )