validates uniqueness of username [SOLVED]

it "validates uniqueness of username attribue" do
    user = User.new(
      username: 'moisesZaragoza',
      password: 'something',
      password_confirmation: 'something'
    )
    user.save
    user2 = User.new(
      username: 'moisesZaragoza',
      password: 'something',
      password_confirmation: 'something'
    )
    user2.should have(1).errors_on(:username)
  end

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :token_authenticatable, :confirmable,
  # :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :password, :password_confirmation, :remember_me, :username, :first_name, :last_name, :account_id
  # attr_accessible :title, :body
  belongs_to :account
--
  validates_uniqueness_of :email, presence: true, :case_sensitive => false
  validates_uniqueness_of :username, presence: true, :case_sensitive => false
  validates :username , :length => { :in => 2..30 }

  validates :first_name, presence: true, :length => { :in => 2..20 }
  validates :last_name, presence: true, :length => { :in => 2..20 }
end