1 files changed, 10 insertions, 0 deletions
diff --git a/test/lib/test/unit/assertions.rb b/test/lib/test/unit/assertions.rb
index 789e2d6c3d..dfa929a136 100644
--- a/test/lib/test/unit/assertions.rb
+++ b/test/lib/test/unit/assertions.rb
@@ -693,6 +693,16 @@ eom
         assert_warning(*args) {$VERBOSE = false; yield}
       end
 
+      def assert_no_warning(pat, msg = nil)
+        stderr = EnvUtil.verbose_warning {
+          EnvUtil.with_default_internal(pat.encoding) {
+            yield
+          }
+        }
+        msg = message(msg) {diff pat, stderr}
+        refute(pat === stderr, msg)
+      end
+
       def assert_no_memory_leak(args, prepare, code, message=nil, limit: 2.0, rss: false, **opt)
         # TODO: consider choosing some appropriate limit for MJIT and stop skipping this once it does not randomly fail
         skip 'assert_no_memory_leak may consider MJIT memory usage as leak' if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled?