test/test-schema.rb in red-arrow-16.0.0 vs test/test-schema.rb in red-arrow-17.0.0

@@ -93,10 +93,10 @@
                      [@schema[0], @schema[1]])
       end
 
       test("[invalid]") do
         invalid = []
-        message = "field name or index must be String, Symbol or Integer"
+        message = +"field name or index must be String, Symbol or Integer"
         message << ": <#{invalid.inspect}>"
         assert_raise(ArgumentError.new(message)) do
           @schema[invalid]
         end
       end