Example subdomain integration test

users_test.rb

require 'test_helper'
  
class Api::UsersTest < ActionDispatch::IntegrationTest                                                                
  def setup
    host! 'api.host.com'
  end                                                                                                                 
                                                                                                                      
  test 'get /v1/users/1.json' do                                                                                      
    user = users(:one)                                                                                                
    get "/v1/users/#{user.id}.json"                                                                                   
    assert_response :success                                                                                          
    assert body.eql?(user.to_json)                                                                                    
    assert JSON.parse(response.body)['username'].eql?(user.username)                                                  
  end 
end