diff --git a/test/readline/test_readline.rb b/test/readline/test_readline.rb
index 73e3df14e61401..28e6b310851fc6 100644
--- a/test/readline/test_readline.rb
+++ b/test/readline/test_readline.rb
@@ -537,6 +537,7 @@ def test_interrupt_in_other_thread
           log << "** NEWLINE **"
           _in.write "\n"
         rescue Errno::EPIPE
+          log << "** Errno::EPIPE **"
           # The "write" will fail if Reline crashed by SIGINT.
         end
         loop do