refute_includes (MiniTest::Assertions)

    # File lib/minitest/unit.rb, line 258
        def refute_includes collection, obj, msg = nil
          msg = message(msg) { "Expected #{mu_pp(collection)} to not include #{mu_pp(obj)}" }
          flip = (obj.respond_to? :include?) && ! (collection.respond_to? :include?) # HACK for specs
          obj, collection = collection, obj if flip
          assert_respond_to collection, :include?
          refute collection.include?(obj), msg
        end