Why Explict Invocation of Callback is Needed in setUp and tearDown?

I got to know nodeunit by reading this article http://caolanmcmahon.com/posts/unit_testing_in_node_js which should been written when nodeunit is at earlier phase. It doesn't mention that explicit invocation of callback function in setUp and tearDown.

There is no documentation about which arguments should be sent by invoking callback in setUp and tearDown. So, I suppose, in most cases, callback is just invoked without any arguments.

Why bother to require explicit invocation of this callback? can't it just be invoked by the system after setUp and tearDown is invoked?

Thanks,
-Morgan

阅读链接的文章，并将其中的 setup 和 teardown 示例与 nodeunit 的当前文档进行比较。确定哪些 callback 参数和调用行为需要说明，然后记录其理由和预期用法；该 issue 未指定具体的文件或测试。

由索引模型根据 Issue 内容生成。