rails--rails/actionview/lib/action_view/testing/resolvers.rb

require 'action_view/template/resolver'

module ActionView #:nodoc:
  # Use FixtureResolver in your tests to simulate the presence of files on the
  # file system. This is used internally by Rails' own test suite, and is
  # useful for testing extensions that have no way of knowing what the file
  # system will look like at runtime.
  class FixtureResolver < PathResolver
    attr_reader :hash

    def initialize(hash = {}, pattern=nil)
      super(pattern)
      @hash = hash
    end

    def to_s
      @hash.keys.join(', ')
    end

  private

    def query(path, exts, formats, _)
      query = ""
      EXTENSIONS.each_key do |ext|
        query << '(' << exts[ext].map {|e| e && Regexp.escape(".#{e}") }.join('|') << '|)'
      end
      query = /^(#{Regexp.escape(path)})#{query}$/

      templates = []
      @hash.each do |_path, array|
        source, updated_at = array
        next unless _path =~ query
        handler, format, variant = extract_handler_and_format_and_variant(_path, formats)
        templates << Template.new(source, _path, handler,
          :virtual_path => path.virtual,
          :format => format,
          :variant => variant,
          :updated_at => updated_at
        )
      end

      templates.sort_by {|t| -t.identifier.match(/^#{query}$/).captures.reject(&:blank?).size }
    end
  end

  class NullResolver < PathResolver
    def query(path, exts, formats, _)
      handler, format, variant = extract_handler_and_format_and_variant(path, formats)
      [ActionView::Template.new("Template generated by Null Resolver", path.virtual, handler, :virtual_path => path.virtual, :format => format, :variant => variant)]
    end
  end
end