rails/actionpack/lib/action_view/test_case.rb

require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/module/delegation'
require 'active_support/core_ext/module/remove_method'
require 'action_controller'
require 'action_controller/test_case'
require 'action_view'

module ActionView
  # = Action View Test Case
  class TestCase < ActiveSupport::TestCase
    class TestController < ActionController::Base
      include ActionDispatch::TestProcess

      attr_accessor :request, :response, :params

      class << self
        attr_writer :controller_path
      end

      def controller_path=(path)
        self.class.controller_path=(path)
      end

      def initialize
        super
        self.class.controller_path = ""
        @request = ActionController::TestRequest.new
        @response = ActionController::TestResponse.new

        @request.env.delete('PATH_INFO')
        @params = {}
      end
    end

    module Behavior
      extend ActiveSupport::Concern

      include ActionDispatch::Assertions, ActionDispatch::TestProcess
      include ActionController::TemplateAssertions
      include ActionView::Context

      include ActionDispatch::Routing::PolymorphicRoutes
      include ActionController::RecordIdentifier

      include AbstractController::Helpers
      include ActionView::Helpers

      delegate :lookup_context, :to => :controller
      attr_accessor :controller, :output_buffer, :rendered

      module ClassMethods
        def tests(helper_class)
          case helper_class
          when String, Symbol
            self.helper_class = "#{helper_class.to_s.underscore}_helper".camelize.safe_constantize
          when Module
            self.helper_class = helper_class
          end
        end

        def determine_default_helper_class(name)
          mod = name.sub(/Test$/, '').constantize
          mod.is_a?(Class) ? nil : mod
        rescue NameError
          nil
        end

        def helper_method(*methods)
          # Almost a duplicate from ActionController::Helpers
          methods.flatten.each do |method|
            _helpers.module_eval <<-end_eval
              def #{method}(*args, &block)                    # def current_user(*args, &block)
                _test_case.send(%(#{method}), *args, &block)  #   _test_case.send(%(current_user), *args, &block)
              end                                             # end
            end_eval
          end
        end

        attr_writer :helper_class

        def helper_class
          @helper_class ||= determine_default_helper_class(name)
        end

        def new(*)
          include_helper_modules!
          super
        end

      private

        def include_helper_modules!
          helper(helper_class) if helper_class
          include _helpers
        end

      end

      def setup_with_controller
        @controller = ActionView::TestCase::TestController.new
        @request = @controller.request
        @output_buffer = ActiveSupport::SafeBuffer.new
        @rendered = ''

        make_test_case_available_to_view!
        say_no_to_protect_against_forgery!
      end

      def config
        @controller.config if @controller.respond_to?(:config)
      end

      def render(options = {}, local_assigns = {}, &block)
        view.assign(view_assigns)
        @rendered << output = view.render(options, local_assigns, &block)
        output
      end

      def locals
        @locals ||= {}
      end

      included do
        setup :setup_with_controller
      end

    private

      # Support the selector assertions
      #
      # Need to experiment if this priority is the best one: rendered => output_buffer
      def response_from_page
        HTML::Document.new(@rendered.blank? ? @output_buffer : @rendered).root
      end

      def say_no_to_protect_against_forgery!
        _helpers.module_eval do
          remove_possible_method :protect_against_forgery?
          def protect_against_forgery?
            false
          end
        end
      end

      def make_test_case_available_to_view!
        test_case_instance = self
        _helpers.module_eval do
          unless private_method_defined?(:_test_case)
            define_method(:_test_case) { test_case_instance }
            private :_test_case
          end
        end
      end

      module Locals
        attr_accessor :locals

        def render(options = {}, local_assigns = {})
          case options
          when Hash
            if block_given?
              locals[options[:layout]] = options[:locals]
            elsif options.key?(:partial)
              locals[options[:partial]] = options[:locals]
            end
          else
            locals[options] = local_assigns
          end

          super
        end
      end

      # The instance of ActionView::Base that is used by +render+.
      def view
        @view ||= begin
          view = @controller.view_context
          view.singleton_class.send :include, _helpers
          view.extend(Locals)
          view.locals = self.locals
          view.output_buffer = self.output_buffer
          view
        end
      end

      alias_method :_view, :view

      INTERNAL_IVARS = [
        :@__name__,
        :@__io__,
        :@_assertion_wrapped,
        :@_assertions,
        :@_result,
        :@_routes,
        :@controller,
        :@layouts,
        :@locals,
        :@method_name,
        :@output_buffer,
        :@partials,
        :@passed,
        :@rendered,
        :@request,
        :@routes,
        :@templates,
        :@options,
        :@test_passed,
        :@view,
        :@view_context_class
      ]

      def _user_defined_ivars
        instance_variables - INTERNAL_IVARS
      end

      # Returns a Hash of instance variables and their values, as defined by
      # the user in the test case, which are then assigned to the view being
      # rendered. This is generally intended for internal use and extension
      # frameworks.
      def view_assigns
        Hash[_user_defined_ivars.map do |ivar|
          [ivar[1..-1].to_sym, instance_variable_get(ivar)]
        end]
      end

      def _routes
        @controller._routes if @controller.respond_to?(:_routes)
      end

      def method_missing(selector, *args)
        if @controller.respond_to?(:_routes) &&
          @controller._routes.named_routes.helpers.include?(selector)
          @controller.__send__(selector, *args)
        else
          super
        end
      end
    end

    include Behavior
  end
end