This gem is responsible for comparing HTML doms and asserting that DOM elements are present in Rails applications.
Doms are compared via
Elements are asserted via
assert_select_email and a subset of the dom can be selected with
The gem is developed for Rails 4.2 and above, and will not work on previous versions.
Nokogiri::CSS::SyntaxError exceptions when upgrading to Rails 4.2:
Nokogiri is slightly stricter about the format of CSS selectors than the previous implementation.
Check the 4.2 release notes section on
assert_select for help.
Add this line to your application's Gemfile:
And then execute:
Or install it yourself as:
$ gem install rails-dom-testing
assert_dom_equal '<h1>Lingua França</h1>', '<h1>Lingua França</h1>' assert_dom_not_equal '<h1>Portuguese</h1>', '<h1>Danish</h1>'
# implicitly selects from the document_root_element css_select '.hello' # => Nokogiri::XML::NodeSet of elements with hello class # select from a supplied node. assert_select asserts elements exist. assert_select document_root_element.at('.hello'), '.goodbye' # elements in CDATA encoded sections can also be selected assert_select_encoded '#out-of-your-element' # assert elements within an html email exists assert_select_email '#you-got-mail'
The documentation in selector_assertions.rb goes into a lot more detail of how selector assertions can be used.
Under the hood the doms are parsed with Nokogiri and you'll generally be working with these two classes:
Read more about Nokogiri:
Contributing to Rails::Dom::Testing
Rails::Dom::Testing is work of many contributors. You're encouraged to submit pull requests, propose features and discuss issues.
Rails::Dom::Testing is released under the MIT License.