title: Rspec: let does not work
body: <p>I have some Rspec tests, where I'm initialising variables with <code>let</code>:</p>
  
  <pre><code>  describe 'methods' do
  
      let(:order)   { Order.new }
      let(:event_1) { FactoryGirl.create(:event) }
      let(:event_2) { FactoryGirl.create(:event) }
  
      context 'should checks if any event is paid' do
        order.events &lt;&lt; event_1
        order.events &lt;&lt; event_2
        order.events_paid?.should == true
      end
  
      context 'should write aasm state' do
        order.aasm_write_state('new')
        order.state.CanonicalName.should == 'new'
      end
  
    end
  </code></pre>
  
  <p>But I get an error <code>'method_missing': 'order' is not available on an example group (e.g. a 'describe' or 'context' block). It is only available from within individual examples (e.g. 'it' blocks) or from constructs that run in the scope of an example (e.g. 'before', 'le', etc). (RSpec::Core::ExampleGroup::WrongScopeError)</code></p>
  
  <p>Why the <code>let</code> initialising is not working?</p>