    # File lib/rack/mock.rb, line 88
        def self.env_for(uri="", opts={})
          uri = parse_uri_rfc2396(uri)
          uri.path = "/#{uri.path}" unless uri.path[0] == ?/

          env = DEFAULT_ENV.dup

          env[REQUEST_METHOD] = opts[:method] ? opts[:method].to_s.upcase : "GET"
          env["SERVER_NAME"] = uri.host || "example.org"
          env["SERVER_PORT"] = uri.port ? uri.port.to_s : "80"
          env[QUERY_STRING] = uri.query.to_s
          env[PATH_INFO] = (!uri.path || uri.path.empty?) ? "/" : uri.path
          env["rack.url_scheme"] = uri.scheme || "http"
          env["HTTPS"] = env["rack.url_scheme"] == "https" ? "on" : "off"

          env[SCRIPT_NAME] = opts[:script_name] || ""

          if opts[:fatal]
            env["rack.errors"] = FatalWarner.new
          else
            env["rack.errors"] = StringIO.new
          end

          if params = opts[:params]
            if env[REQUEST_METHOD] == "GET"
              params = Utils.parse_nested_query(params) if params.is_a?(String)
              params.update(Utils.parse_nested_query(env[QUERY_STRING]))
              env[QUERY_STRING] = Utils.build_nested_query(params)
            elsif !opts.has_key?(:input)
              opts["CONTENT_TYPE"] = "application/x-www-form-urlencoded"
              if params.is_a?(Hash)
                if data = Utils::Multipart.build_multipart(params)
                  opts[:input] = data
                  opts["CONTENT_LENGTH"] ||= data.length.to_s
                  opts["CONTENT_TYPE"] = "multipart/form-data; boundary=#{Utils::Multipart::MULTIPART_BOUNDARY}"
                else
                  opts[:input] = Utils.build_nested_query(params)
                end
              else
                opts[:input] = params
              end
            end
          end

          empty_str = ""
          empty_str.force_encoding("ASCII-8BIT") if empty_str.respond_to? :force_encoding
          opts[:input] ||= empty_str
          if String === opts[:input]
            rack_input = StringIO.new(opts[:input])
          else
            rack_input = opts[:input]
          end

          rack_input.set_encoding(Encoding::BINARY) if rack_input.respond_to?(:set_encoding)
          env['rack.input'] = rack_input

          env["CONTENT_LENGTH"] ||= env["rack.input"].length.to_s

          opts.each { |field, value|
            env[field] = value  if String === field
          }

          env
        end