def METHOD_NAME(self):
    with self.app.app_context():
        submissions = db.engine.execute(text("SELECT * FROM submissions")).fetchall()
        # Submissions without a source should be deleted
        assert len(submissions) == 1
        for submission in submissions:
            assert submission.source_id == self.valid_source_id
        replies = db.engine.execute(text("SELECT * FROM replies")).fetchall()
        # Replies without a source should be deleted
        assert len(replies) == 1
        for reply in replies:
            assert reply.source_id == self.valid_source_id