1 files changed, 5 insertions, 0 deletions
diff --git a/test/ruby/envutil.rb b/test/ruby/envutil.rb
index 8d7a1eef24..7b235106cb 100644
--- a/test/ruby/envutil.rb
+++ b/test/ruby/envutil.rb
@@ -173,6 +173,11 @@ module Test
         assert(status.success?, m)
       end
 
+      def assert_warn(msg)
+        stderr = EnvUtil.verbose_warning { yield }
+        assert(msg === stderr, "warning message #{stderr.inspect} is expected to match #{msg.inspect}")
+      end
+
     end
   end
 end