The skeleton test-generating-docs example I built to exhibit the framework actually does this. Here's an example:

https://github.com/hitchdev/hitchstory/blob/master/examples/...

It records a video while running the test and then at the end runs it through FFMPEG to make a smaller, slowed down GIF that can be embedded in the autogenerated docs.

It's quite rudimentary though. I've been meaning to try making something more sophisticated and even potentially do additional automated video editing to inject text from the steps or something.