diff --git a/test/ruby/bug-13526.rb b/test/ruby/bug-13526.rb
index e0b8e981cc..50c6c67a7d 100644
--- a/test/ruby/bug-13526.rb
+++ b/test/ruby/bug-13526.rb
@@ -18,5 +18,5 @@ threads = Array.new(n) do
   end
 end
 
-Thread.pass while threads.all?(&:stop?)
+Thread.pass until threads.all?(&:stop?)
 1000.times { Thread.pass }