Gemini Lasswell <gazally@runbox.com> writes:

> This is an excerpt of test/src/fns-tests.el with a few lines added at
> the end to invoke Testcover. It contains two nearly identical tests
> which should both pass, but one passes and one fails.

If I run them again in the same Emacs session then they both fail.  The
problem seems to be that testcover saves values produced in tests, and
when it tries to compare the 2 circular lists produced by these tests, a
`circular-list' error is thrown.  In other words, this is actually a
totally separate bug (although it's hidden until a fix for #24402 is
applied).

The following appears to fix it, though perhaps we should use a smarter
equal function that would consider the circular lists to actually be
equal instead of bailing out and returning nil on circularity.