:date: 2020-10-22

==========================
Thursday, October 22, 2020
==========================

The getlino test suite now also tries to install a voga application. And this
failed.  The :manage:`prep` on the newly created site said::

  lino_xl.lib.ledger.models.DoesNotExist:
  Problem installing fixture '/usr/local/lino/lino_local/voga1/env/lib/python3.7/site-packages/lino_xl/lib/finan/fixtures/payments.py':
  Journal matching query does not exist.

I reproduced this problem in the book by adding a new demo project
:mod:`lino_book.projects.voga1`.

Explanation: the :fixture:`minimal_ledger` in :mod:`lino_xl.lib.ledger` created
certain journals (SLC, PRC, PMO, ...) only when
:attr:`lino_xl.lib.vat.Plugin.declaration_plugin` was set.  And there is no
default value for this setting.
An empty :attr:`declaration_plugin <lino_xl.lib.vat.Plugin.declaration_plugin>` is used e.g. in
:mod:`lino_book.projects.pierre`, which is an example of a freelancer who uses
Lino to just write invoices and has accounting done by an external expert.

Should getlino ask (or provide a default value) for it? No. The solution is much
easier:

- Adapted the :fixture:`payments` fixture of :mod:`lino_xl.lib.ledger` to also
  work when :attr:`declaration_plugin
  <lino_xl.lib.vat.Plugin.declaration_plugin>` is empty.

- Fixing this revealed a secondary bug: the :meth:`get_installed_plugins` of the
  :class:`lino_voga.lib.voga.settings.Site` was yielding the
  :mod:`lino_xl.lib.bevats` plugin, this is done automatically when
  :attr:`declaration_plugin <lino_xl.lib.vat.Plugin.declaration_plugin>` is set.