diff --git a/test/webrick/test_httpresponse.rb b/test/webrick/test_httpresponse.rb
index 48f8ace..8373453 100644
--- a/test/webrick/test_httpresponse.rb
+++ b/test/webrick/test_httpresponse.rb
@@ -272,7 +272,7 @@ def test_send_body_proc_upgrade
       IO.pipe do |r, w|
         @res.send_response(w)
         w.close
-        assert_match /Connection: upgrade\r\nUpgrade: text\r\n\r\nhello/, r.read
+        assert_match(/Connection: upgrade\r\nUpgrade: text\r\n\r\nhello/, r.read)
       end
       assert_empty logger.messages
     end
@@ -292,7 +292,7 @@ def test_send_body_proc_stream
         s2.write("hello")
         s2.close_write
         chunk = s2.read
-        assert_match /Connection: close\r\n\r\nhello/, chunk
+        assert_match(/Connection: close\r\n\r\nhello/, chunk)
         s2.close
 
         thread.join