expect(ability).to be_able_to(:destroy, Project.new(:user => user))

NoMethodError: undefined method `expect' for main:Object

require 'spec_helper'
  require "cancan/matchers"

  describe Ability do
    it "user has ability" do
      user = FactoryGirl.create(:user)
      ability = Ability.new(user)
      expect(ability).to be_able_to(:destroy, Project.new(:user => user))
    end
  end

2.1.5 :004 >     expect(ability).to be_able_to(:destroy, Project.new(:user => user))
NoMethodError: undefined method `expect' for main:Object
    from (irb):4
    from /home/weare138/.rvm/gems/ruby-2.1.5/gems/railties-4.1.4/lib/rails/commands/console.rb:90:in `start'
    from /home/weare138/.rvm/gems/ruby-2.1.5/gems/railties-4.1.4/lib/rails/commands/console.rb:9:in `start'
    from /home/weare138/.rvm/gems/ruby-2.1.5/gems/railties-4.1.4/lib/rails/commands/commands_tasks.rb:69:in `console'
    from /home/weare138/.rvm/gems/ruby-2.1.5/gems/railties-4.1.4/lib/rails/commands/commands_tasks.rb:40:in `run_command!'
    from /home/weare138/.rvm/gems/ruby-2.1.5/gems/railties-4.1.4/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'
2.1.5 :005 >

bundle exec rspec path/to/ability_spec.rb

bundle exec rspec .