diff --git a/test/test_timeout.rb b/test/test_timeout.rb
index 7421b5b..199b18e 100644
--- a/test/test_timeout.rb
+++ b/test/test_timeout.rb
@@ -444,5 +444,5 @@ def test_timeout_in_trap_handler
 
     assert_equal "OK", rd.read
     rd.close
-  end
+  end if Signal.list["USR1"] # Windows has no SIGUSR1
 end