Have test runner show diff between "actual" and "expected"

[svdo]

It would be awesome if the test runner would (in the Calva output) not just show what was the expected and actual output, but also what's the difference between the two. We've been using the "ultra" leiningen plugin in the terminal for this, which shows it super-super-nicely (see https://github.com/venantius/ultra/wiki/Tests). I don't know if they use some library that can be reused by Calva...?

[bpringe]

Looks like they use clojure.data.diff, at least for some or most of the diffs: https://github.com/venantius/ultra/blob/c254cb96d6f7b05773c32e2925d8f87761780936/src/ultra/test.clj#L13

[svdo]

There is also this btw: https://github.com/lambdaisland/deep-diff2. I like the rendering of the diffs from Ultra better than those from Kaocha, but maybe the diff engine is easier to integrate?

[mrkam2]

Here is cider-nrepl implementation of test output diffing: https://github.com/clojure-emacs/cider-nrepl/blob/a53ab41c7ae56fda9f4a7b5916c5bd1f8fa60d95/src/cider/nrepl/middleware/test/extensions.clj#L22-L23.

[bpringe]

So is that the wrap-test middleware supplied by cider-nrepl? If if is, then I think if that middleware is present in the running repl then Calva should be getting that diff info already. We may just need to display it in the output window.