Testing a redirect outside of a controller

I have a helper module with a method that fires off redirect_to if the current user does not have permission to visit a web page.

I am getting a NoMethodError error when running the tests, since the helper does not actually have a redirect_to method. I have tried stubbing out redirect_to like this:

it "redirects the user to the user's langing page if the user doesn't have permission" do
  allow(helper).to receive(:current_or_guest_user) { test_user }
  expect(helper).to receive(:redirect_to)
  helper.require_permission :view_admins
end

but I get a long long error that the helper does not implement redirect_to.

Is there a way to stub out this method?