Ruby tests breaking

[jackkamm]

When I tried to run the unit tests today, the ruby tests all broke with errors like:

    (ert-test-failed
     ((should
       (progn
	 (org-babel-execute-src-block)
	 (sleep-for 0 400)
	 (string= ... ...)))
      :form
      (progn
	(org-babel-execute-src-block)
	(sleep-for 0 400)
	(string=
	 (concat src-block result)
	 (buffer-string)))
      :value nil))

When I last tried in October (https://github.com/jackkamm/ob-session-async/pull/2) the tests worked.

I'm running on Archlinux, ruby 2.6.5, irb 1.1.0. When I tried on a Debian VM, the tests still worked. So I suspect a Ruby or IRB update broke something.

Perhaps relatedly, when I run irb, I get the following message:

This version of IRB is drastically different from the previous version.
If you hit any issues, you can use "irb --legacy" to run the old version.
If you want to just erase this message, please use "irb --multiline".
irb(main):001:0>