diff --git a/tool/lib/test/unit.rb b/tool/lib/test/unit.rb
index 5fbb8db1a9..c489e5ab66 100644
--- a/tool/lib/test/unit.rb
+++ b/tool/lib/test/unit.rb
@@ -530,7 +530,7 @@ module Test
           @workers.each do |worker|
             worker.kill
           end
-          @worker.clear
+          @workers.clear
         end
       end