Do a functional doctest test on the app.
========================================

:Test-Layer: functional

Let's first create an instance of Sample at the top level:

   >>> from sample.app import Sample
   >>> root = getRootFolder()
   >>> root['app'] = Sample()


Run tests in the testbrowser
----------------------------

The zope.testbrowser.browser module exposes a Browser class that
simulates a web browser similar to Mozilla Firefox or IE.  We use that
to test how our application behaves in a browser.  For more
information, see http://pypi.python.org/pypi/zope.testbrowser.

Create a browser and visit the instance you just created:

   >>> from zope.testbrowser.testing import Browser
   >>> browser = Browser()
   >>> browser.open('http://localhost/app')

Check some basic information about the page you visit:

   >>> browser.url
   'http://localhost/app'
   >>> browser.headers.get('Status').upper()
   '200 OK'
