friendfeed | project created by a handful of FriendFeed enthusiasts

Noob here. I want to build a personal blog using Hexo with theme next, but I met some problems (no problems with other themes, e.g. landscape). I typed hexo s -g Cmd line returns

I'm using tornado.ioloop.IOLoop.run_in_executor to change a synchronous function to asynchrounous, but it turns out that each time the function is called, there is a thread created but not killed.

Here's an mimimal reproducible example (at least reproducible on my machine):

Environment: Python 3, tornado 4.4. The normal unittests cannot be used because methods are asynchronous. There is ttp://www.tornadoweb.org/en/stable/testing.html that explains how to do unit testing for asynchronous code. But that works with tornado coroutines ONLY. The classes I want to test are using the async def statements, and they cannot be tested this way. For example, here is a test case that uses ASyncHTTPClient.fetch and its callback parameter: