class Domain < ActiveRecord::Base
  belongs_to :user
  has_many :ranks, dependent: :destroy
  validates_uniqueness_of :name, scope: :user_id, message: "You alredy entered that domain"
  validates_presence_of :name
  validate :user_quota, on: :create

  def user_quota
    errors.add(:base, 'OOps!!! You have Exceeded maximum domain limit/user (3)')  if self.user.domains(:reload).count >= 3
  end
end

require 'rails_helper'

RSpec.describe Domain, type: :model do
  it " - cannot create a new domain if user already have 3 domains" do
  user = User.create(name: "John Doe", email: 'jane@doe.com', password: 'pw1234',
  password_confirmation: 'pw1234')
  user_domain1 = Domain.create(name: 'http://example1.com', user_id: user.id,
             created_at: DateTime.now, updated_at: DateTime.now)
  expect(user_domain1.errors).to be_empty

  user_domain2 = Domain.create(name: 'http://example2.com', user_id: user.id,
             created_at: DateTime.now, updated_at: DateTime.now)
  expect(user_domain1.errors).to be_empty

  user_domain3 = Domain.create(name: 'http://example3.com', user_id: user.id,
             created_at: DateTime.now, updated_at: DateTime.now)
  expect(user_domain1.errors).to be_empty

  user_domain1 = Domain.create(name: 'http://example1.com', user_id: user.id,
             created_at: DateTime.now, updated_at: DateTime.now)
  expect(user_domain1.errors).to_not be_empty
  end
end

Failure/Error: errors.add(:base, 'OOps!!! You have Exceeded maximum       domain limit/user (3)')  if self.user.domains(:reload).count >= 3

 NoMethodError:
   undefined method `domains' for nil:NilClass