Add a test to check if name already exists

Change-Id: Ie23de04c0b747f58ab61a6e498bf212bf38b346a
Reviewed-on: https://gerrit.libreoffice.org/16000Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit 3807946b)
Reviewed-on: https://gerrit.libreoffice.org/16055Reviewed-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>
Tested-by: Jenkins <ci@libreoffice.org>