Thanks for the link to the previous discussion, Dmitry.

Dmitry:
>> Don't you think it would be better to have these tests in
>> test/automated/ruby-mode-tests.el?

Stefan:
> I find it inconvenient, actually, because when the test fails, it's
> a handy to be able to have a ruby-mode buffer where I can try out
> sexp movement and indentation functions "in the usual way", together
> with Edebug if needed.

Surely there's a way to provide this debugging use case without
ostracizing the test from the automated test suite. Why not have a
ert-with-temp-buffer which if the test fails (within the form), a file
would be saved off with the buffer contents. Ideally the test case
name would be in the generated filename.

Stefan:
> use test/indent the general indentation rules, and use ERT rules to
> check how indentation obeys the various indentation variables

It looks like the test/indent tests are only good for null-diff
general indentation rules. And worst of all not automated.