l10n_generic_coa.demo_invoice_followup invoice

[MPishpecki]

created after new year, causes test to break. linking
the invoice with a dummy statement excludes the
invoice move lines from tests.

[astirpe]

This proposed fix could create confusion in case of not-yet new year. I would prefer to fix the travis error by changing
self.assertEqual(len(statement2.unreported_move_ids), 1)
to
self.assertGreaterEqual(len(statement2.unreported_move_ids), 1)