diff --git a/test/irb/test_debug_cmd.rb b/test/irb/test_debug_cmd.rb
index 9aafbec7f..4d1bb6d6b 100644
--- a/test/irb/test_debug_cmd.rb
+++ b/test/irb/test_debug_cmd.rb
@@ -1,6 +1,11 @@
 # frozen_string_literal: true
 
-require "pty" unless RUBY_ENGINE == 'truffleruby'
+begin
+  require "pty"
+rescue LoadError
+  return
+end
+
 require "tempfile"
 require "tmpdir"
 require "envutil"