This tests the behaviour when removing an object which is referencing
some page or image and at the same time is referenced by a third.  This
should result in no confirmation form whatsoever, of course:

  >>> self.setRoles(('Manager',))
  >>> p = self.portal
  >>> p.doc1.processForm(values={'text':'<a href="folder1/doc5">a document</a>'})
  >>> p.folder1.doc4.processForm(values={'text':'<a href="doc3">a document</a>'})
  >>> p.doc1.getReferences()
  [<ATDocument at /plone/folder1/doc5>]
  >>> p.folder1.doc4.getReferences()
  [<ATDocument at /plone/folder1/doc3>]

Then we use a browser to try to delete all three documents
involved above.  Before we can do this we need to prevent the test
framework from choking on the exception we intentionally throw (see
docs/testRemovalTriggersConfirmation.txt for more info):

  >>> self.setStatusCode('LinkIntegrityNotificationException', 200)
  >>> browser = self.getBrowser(loggedIn=True)
  >>> browser.open('http://nohost/plone/folder_contents')
  >>> browser.getControl('Test Page 1').selected = True
  >>> browser.getControl('Test Folder 1').selected = True
  >>> browser.getControl('Delete').click()
  >>> browser.url
  'http://nohost/plone/@@folder_contents'
  >>> browser.contents
  '...<dl class="portalMessage...Item(s) deleted...</dl>...'

The documents should have been deleted:

  >>> portal.doc1
  Traceback (most recent call last):
  ...
  AttributeError: doc1
  >>> portal.folder1.doc4
  Traceback (most recent call last):
  ...
  AttributeError: folder1

