# File lib/shoulda/context/assertions.rb, line 37
      def assert_does_not_contain(collection, x, extra_msg = "")
        collection = Array(collection)
        msg = "#{x.inspect} found in #{collection.to_a.inspect} " + extra_msg
        case x
        when Regexp
          assert(!collection.detect { |e| e =~ x }, msg)
        else
          assert(!collection.include?(x), msg)
        end
      end