bug#74090: 31.0.50; Problems with dabbrev-expand

[Stephen Berman via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

On Tue, 03 Dec 2024 09:35:30 +0200 Juri Linkov <juri@linkov.net> wrote:

>> With these changes the test succeeds in batch runs and I think now better
>> reflects the user experience with manual input, so I went ahead and
>> pushed the fix (commit 6bca138d60e to emacs-30).  If you agree, feel
>> free to close the bug again (assuming it needs to be reclosed, since you
>> unarchived it); otherwise, if you see other problems with the test,
>> please let me know.
>
> I see the same test failures that were reported on emacs-devel.
>
> One of them is clear because of quotes mismatch:
>
>       (string= "No further dynamic expansion for `ab' found"
> 	       "No further dynamic expansion for ‘ab’ found")

Thanks, I've (hopefully) fixed this problem now (or rather avoided it,
since the change is just a workaround) with commit 7b8d12e95de to
emacs-30.

> But why 4 lines with should-error affect two other tests
> is not clear.  Maybe other tests expect the initial contents
> in the scratch buffer?  Or the same buffer list?

Those other tests are two of the four dabbrev-expand-other-buffer* tests
that also fail when manually running ert in the test buffer.  I couldn't
figure out why but since these tests succeed in batch runs and with
`make check', I haven't investigated further, but I'll try to do that.

> Generally, this is deficiency of the test-suite design
> that tests are not isolated.

The macro `with-dabbrev-test' is supposed to ensure that, but maybe it's
failing somehow.

Steve Berman