registration_controller_test.rb

require 'rails_helper'

RSpec.describe RegistrationController do
  include Devise::Test::ControllerHelpers

  describe 'POST /users for user' do
    let(:user) {
      {
        email: "[email protected]",
        password:  "master-tester",
        user_profile_attributes: {
          name: "Tester Name",
          last_name: "Tester Surname",
          bitrh_date: 21.years.ago,
          city_id: 1,
          sex: 'M',
          phone: 123456789
        }
      }.as_json

     }
     before(:each) do
      @request.env["devise.mapping"] = Devise.mappings[:user]
     end

    it_behaves_like 'check delivery', :create, { :user => {
      email: "[email protected]",
      password:  "master-tester",
      user_profile_attributes: {
        name: "Tester Name",
        last_name: "Tester Surname",
        bitrh_date: 21.years.ago,
        city_id: 1,
        sex: 'M',
        phone: 123456789
      }
    }.as_json},  "[email protected]"

  end
end

shared_examples.rb

RSpec.shared_examples "check delivery" do |action, params, recipient|
  include ActiveJob::TestHelper

  before do
    @request.env["devise.mapping"] = Devise.mappings[:user]
    clear_enqueued_jobs
  end
  it "sends an email to recipient: #{recipient}" do
    expect { post action, params: params }.to change { enqueued_jobs.size }.by(1)
    # ....
  end
end