Rspec - include helper within controller

I'd like to use helper method during I test my controller

event_controller_spec.rb

require 'rails_helper'
require 'spec_helper'

RSpec.describe EventsController do
  describe 'method' do
    it do
      foo
    end
  end
end

events_helper.rb

module EventsHelper
 def foo
 end
end

but I get failure like this:

undefined local variable or method `foo' for #<RSpec::ExampleGroups::EventsController::Method:0x00000006671fa0>

So my question is as I mentioned earlier: how to include methods to test some controller/helper from others controllers/helpers. I tried require file same as spec_helper for instance but it changes nothing.