register_parser

Register a callable to parse rendered content for a given template format.

Each registered parser will also define a +#rendered.[FORMAT]+ helper method, where +[FORMAT]+ corresponds to the value of the format argument.

By default, ActionView::TestCase defines parsers for:

• :html - returns an instance of +Nokogiri::XML::Node+

• :json - returns an instance of ActiveSupport::HashWithIndifferentAccess

These pre-registered parsers also define corresponding helpers:

• :html - defines rendered.html

• :json - defines rendered.json

Parameters

format

The name (as a Symbol) of the format used to render the content.

callable

The parser. A callable object that accepts the rendered string as its sole argument. Alternatively, the parser can be specified as a block.

Examples

test "renders HTML" do
  article = Article.create!(title: "Hello, world")

  render partial: "articles/article", locals: { article: article }

  assert_pattern { rendered.html.at("main h1") => { content: "Hello, world" } }
end

test "renders JSON" do
  article = Article.create!(title: "Hello, world")

  render formats: :json, partial: "articles/article", locals: { article: article }

  assert_pattern { rendered.json => { title: "Hello, world" } }
end

To parse the rendered content into RSS, register a call to +RSS::Parser.parse+:

register_parser :rss, -> rendered { RSS::Parser.parse(rendered) }

test "renders RSS" do
  article = Article.create!(title: "Hello, world")

  render formats: :rss, partial: article

  assert_equal "Hello, world", rendered.rss.items.last.title
end

To parse the rendered content into a +Capybara::Simple::Node+, re-register an :html parser with a call to Capybara.string:

register_parser :html, -> rendered { Capybara.string(rendered) }

test "renders HTML" do
  article = Article.create!(title: "Hello, world")

  render partial: article

  rendered.html.assert_css "h1", text: "Hello, world"
end

# File actionview/lib/action_view/test_case.rb, line 148
        def register_parser(format, callable = nil, &block)
          parser = callable || block || :itself.to_proc
          content_class.redefine_method(format) do
            parser.call(to_s)
          end
        end