diff --git a/lib/fluent/test/driver/filter.rb b/lib/fluent/test/driver/filter.rb
index 8d07e7810b..0d6adb13da 100644
--- a/lib/fluent/test/driver/filter.rb
+++ b/lib/fluent/test/driver/filter.rb
@@ -38,7 +38,7 @@ def filtered_records
         end
 
         def filtered_time
-          @filtered.map {|_time, record| _time }
+          @filtered.map {|time, _record| time }
         end
 
         def instance_hook_after_started