How to test after_sign_in_path_for by minitest - ruby-on-rails

Question

I changed the default behavior of after_sign_in_path_for method like this:
class ApplicationController < ActionController::Base
private
def after_sign_in_path_for(resource)
return admin_root_path if resource.is_a?(AdminUser)
request.referrer || root_path
end
end
It works find and now I want to test it by minitest.
But I couldn't figure out how to write integration test for it.
Although there is an answer for rspec, I couln't rewrite for minitest.
How to test after_sign_in_path_for(resource)?
How can I write the test for after_sign_in_path_for by minitest?
Rails: 5.1
devise: 4.5.0
require 'test_helper'
class ApplicationControllerTest < ActionDispatch::IntegrationTest
include Devise::Test::IntegrationHelpers
setup do
2.times{ create(:post) }
#user = create(:user)
#admin_user = create(:admin_user)
end
test "should redirect to '/posts/1' after login" do
# get "/posts/1"
# sign_in(#user)
# test return back "/posts/1"
end
test "should redirect to '/posts/2' after login" do
# get "/posts/2"
# sign_in(#user)
# test return back "/posts/2"
end
test "should redirect to admin root page after login" do
# sign_in(#adminuser)
# test go to admin root page
end
end

Answer 1

You can test them like so:
require 'test_helper'
class ApplicationControllerTest < ActionDispatch::IntegrationTest
include Devise::Test::IntegrationHelpers
setup do
#user = create(:user)
#admin_user = create(:admin_user)
end
test "should redirect to current page after login" do
sign_in(#user)
get :index
assert_redirected_to controller: "home", action: "index"
end
test "should redirect to admin root page after login" do
sign_in(#adminuser)
get :index
assert_redirected_to controller: "admin", action: "index"
end
end
assert_redirected_to API docs