diff --git a/test/readline/test_readline.rb b/test/readline/test_readline.rb
index 0e64b1f027..f659ba24c5 100644
--- a/test/readline/test_readline.rb
+++ b/test/readline/test_readline.rb
@@ -4,6 +4,7 @@ rescue LoadError
 else
   require "test/unit"
   require "tempfile"
+  require "timeout"
 end
 
 class TestReadline < Test::Unit::TestCase
@@ -398,7 +399,9 @@ class TestReadline < Test::Unit::TestCase
         w << "\cr\u3042\u3093"
         w.reopen(IO::NULL)
         assert_equal("\u3046\u3093", Readline.readline("", true), bug6602)
-        assert_equal("\u3042\u3093", Readline.readline("", true), bug6602)
+        Timeout.(2) do
+          assert_equal("\u3042\u3093", Readline.readline("", true), bug6602)
+        end
         assert_equal(nil,            Readline.readline("", true), bug6602)
       end
     end