Best way to test output helpers

[tonekk]

Hi community,

I'm looking for the best way to test an output helper.
By output helper I am not referring to a helper imported from rails helpers, but instead just a method that outputs markup, which is used by subclasses, like:

class ApplicationComponent < Phlex::HTML
  def plausible_event(event_name, options = {})
    template(
      data: {
        plausible_event: event_name,
        plausible_options: options.to_json
      }
    )
  end
end

Calling this method directly in a spec will lead to an error ("buffer not found" or similar).
My current approach is subclassing the component and use view_template, but it feels a little awkward.

require "rails_helper"

describe ApplicationComponent, type: :component do
  describe "#plausible_event" do
    it "renders declarative event and props hints" do
      component_class = Class.new(ApplicationComponent) do
        def view_template
          plausible_event("Test: Some Event", {props: {test_details: "XYZ"}})
        end
      end

      node = Capybara.string(component_class.call)

      expect(node).to have_css(%(template[data-plausible-event='Test: Some Event']), visible: false)
      expect(node).to have_css(%(template[data-plausible-options='{"props":{"test_details":"XYZ"}}']), visible: false)
    end
  end
end

Is there an easier solution?

Thanks!