Fixed frozen string warnings with tests [skip ci]

ankane · ankane · commit 946233fe7183 · 2025-02-03T18:28:04.000-08:00
diff --git a/test/test_helper.rb b/test/test_helper.rb
@@ -7,7 +7,7 @@
 
 class Minitest::Test
   def setup
-    @output = StringIO.new("")
+    @output = StringIO.new(+"")
     @output_checked = false
 
     GC.stress = true if stress?
