def check_content_type(status, headers)
      headers.each { |key, value|
        ## There must be a <tt>Content-Type</tt>, except when the
        ## +Status+ is 1xx, 204 or 304, in which case there must be none
        ## given.
        if key.downcase == "content-type"
          assert("Content-Type header found in #{status} response, not allowed") {
            not Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.include? status.to_i
          }
          return
        end
      }
      assert("No Content-Type header found") {
        Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.include? status.to_i
      }
    end
def check_content_type(status, headers)
      headers.each { |key, value|
        ## There must be a <tt>Content-Type</tt>, except when the
        ## +Status+ is 1xx, 204 or 304, in which case there must be none
        ## given.
        if key.downcase == "content-type"
          assert("Content-Type header found in #{status} response, not allowed") {
            not Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.include? status.to_i
          }
          return
        end
      }
      assert("No Content-Type header found") {
        Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.include? status.to_i
      }
    end
=== The Content-Type