Today, driven by annoyance, I refactor-extracted a small set of test helper code found in various private personal projects around the topic of golden file management into a dedicated Go module: github.com/matttproud/goldentest (API documentation). I’m happy to finally have a canonical solution that I am happy with. I’ll freely admit it: I use change detector tests1 for some things, as a slew of these personal projects use reference data defined in the testdata directory as canonical want values that got is compared against. It’s practical: for code that generates HTML files, I can inspect the files in a browser or local web server and verify behavior conformance. Same goes for end-to-end tests that generate output. In select cases, it is easier than redefining onerous data literals in my test themselves — not that I like indirection all that much.

Unit tests verify logic in isolation. Widget tests verify UI in a simulated environment. Neither catches the permission dialog your app…