"id buttonization" test failure

[Marius Bakke]

Hi,

I'm trying to run the test suite on GNU Guix and get a mysterious test
failure in T450-emacs-show.sh:

T450-emacs-show: Testing emacs notmuch-show view
 [...]
 PASS   [11] notmuch-show: disable indentation of thread content (w/ notmuch-show-toggle-thread-indentation)
 FAIL   [12] id buttonization
        --- T450-emacs-show.13.OUTPUT   2016-10-06 01:42:21.329950576 +0000
        +++ T450-emacs-show.13.EXPECTED 2016-10-06 01:42:21.329950576 +0000
        @@ -23,4 +23,4 @@
         cid:xxx
         <<mid:abc>> <<mid:abc/def>>
         <<mid:abc%20def>>
        -<<mid:a>>bc. <<mid:abc>>, <<mid:abc>>;
        +<<mid:abc>>. <<mid:abc>>, <<mid:abc>>;
nil
 PASS   [13] Show handles subprocess errors

Any idea what's going on here? It's using emacs-25.1.

Thanks!