'Test that two nodes that should have a parent_of relationship have it.'

def test_parent_relationship(self):

    (__, relationships) = serialize_course(self.course.id)
    self.assertBlockPairIsRelationship(self.vertical, self.video, relationships, u'PARENT_OF')
    self.assertBlockPairIsRelationship(self.vertical, self.html, relationships, u'PARENT_OF')
    self.assertBlockPairIsRelationship(self.course, self.chapter, relationships, u'PARENT_OF')
    self.assertBlockPairIsNotRelationship(self.course, self.video, relationships, u'PARENT_OF')
    self.assertBlockPairIsNotRelationship(self.video, self.vertical, relationships, u'PARENT_OF')
    self.assertBlockPairIsNotRelationship(self.video, self.html, relationships, u'PARENT_OF')
