Note: assert_selector only matches on visible elements by default. To match on elements regardless of visibility, add visible: false. See the Capybara documentation for more details.
In the absence of capybara, assert against the return value of render_inline, which is an instance of Nokogiri::HTML::DocumentFragment:
Component tests assume the existence of an ApplicationController class, which can be configured globally using the test_controller option:
Some Rails helpers won’t work unless request.path_parameters are set correctly, resulting in an ActionController::UrlGenerationError.