title: rails 2.3.10 open_session - method missing
body: <p>I'm trying to write some tests for an old app:</p>
  
  <pre><code>open_session do |sess|
    sess.post "/shop/cart/add", :product_id =&gt; 687, :quantity =&gt; 1
    assert_equal '/shop/cart', path
  end
  </code></pre>
  
  <p>I just need to test the checkout process but the app needs session data to do so. When I use open_session I get:</p>
  
  <pre><code>NameError: undefined local variable or method `open_session' for #&lt;OrderTest:0x10706cf68&gt;
  </code></pre>