How do you test a Rails controller method exposed as a helper_method?

Question

They don\'t seem to be accessible from ActionView::TestCase

Answer 1

This feels awkward, because you're getting around encapsulation by using send on a private method.

A better approach is to put the helper method in a module in the /controller/concerns directory, and create tests specifically just for this module.

e.g. in app controller/posts_controller.rb

class PostsController < ApplicationController
  include Formattable
end

in app/controller/concerns/formattable.rb

  module Concerns
    module Formattable
      extend ActiveSupport::Concern # adds the new hot concerns stuff, optional

      def format_something
        "abc"
      end
    end
  end

And in the test/functional/concerns/formattable_test.rb

require 'test_helper'

# setup a fake controller to test against
class FormattableTestController
  include Concerns::Formattable
end

class FormattableTest < ActiveSupport::TestCase

 test "the format_something helper returns 'abc'" do
    controller = FormattableTestController.new
    assert_equal 'abc', controller.format_something
  end

end