bug#28319: emacsclient tests interfere with running Emacs, hang

[Glenn Morris]

Reuben Thomas wrote:

> The main thing I don't understand is why this behavior isn't a problem for
> other tests that use call-process, except that they don't seem to check the
> return value;

They do use the return value, eg info-xref-test-write-file.
I think it is something specific to emacsclient when compiled with "-pg".
(But I don't really know anything about this.)