[xiaq]

I don't have a version with captions, sorry. You can find the slidedeck at https://github.com/elves/elvish/blob/master/website/slides/2...

The remaining 8% mostly falls into the following categories:

- Code that use OS functionalities that are cumbersome to mock in tests

- Code paths that are triggered relatively rarely and I was simply too lazy to add tests for them

Nothing is impossible to cover, but for whatever reason it was too much work for me when I wrote the code.

However, it's worth mentioning that I only settled on the transcript test pattern fairly recently, and if I were to rewrite or refactor some of the untested code today I would add tests for them, because the cost of adding tests has been lowered considerably. So Elvish's test coverage is still increasing slowly as the cost of testing decreases.