18 Aug 2025I’ve been working on a CLI tool recently, and one of the things it does is manage files on disk. I have written a lot of file management tests for Bundler, and the two biggest reasons that the Bundler test suite is slow are exec and fstat. Knowing that, I thought I would try to get out ahead of the slow file stat problem by using an in-memory filesystem for testing.A collaborator mentioned being happy with the Go package named Afero for this purpose, and so I set off to look for a Rus...