diff --git a/test/ruby/test_process.rb b/test/ruby/test_process.rb
index 93eb871edc..1e9ad4d457 100644
--- a/test/ruby/test_process.rb
+++ b/test/ruby/test_process.rb
@@ -36,6 +36,6 @@ class TestProcess < Test::Unit::TestCase
       exit 1
     }
     Process.wait pid
-    assert_equal(0, $?.to_i)
+    assert_equal(0, $?.to_i, "#{$?}")
   end
 end