'mode is auto-generated from inherit_id:
* inherit_id -> mode=extension
* not inherit_id -> mode=primary'

def testModeImplicitValue(self):

    view = self.View.create({'inherit_id': None, 'arch': '<qweb/>'})
    self.assertEqual(view.mode, 'primary')
    view2 = self.View.create({'inherit_id': view.id, 'arch': '<qweb/>'})
    self.assertEqual(view2.mode, 'extension')
