should_method?

# File lib/spec/example/example_group_methods.rb, line 427
      def should_method?(method_name)
        !(method_name =~ /^should(_not)?$/) &&
        method_name =~ /^should/ && (
          instance_method(method_name).arity == 0 ||
          instance_method(method_name).arity == -1
        )
      end