Set reference to Pay Sheet Model Line.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@30882 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/tests/testPayroll.py

@@ -1703,6 +1703,7 @@ class TestPayrollMixin(ERP5ReportTestCase, TestTradeModelLineMixin):
     labour = sequence.get('labour_service_output')
     line = model.newContent(
           id='line',
+          reference='zero_price_line',
           portal_type='Pay Sheet Model Line',
           resource_value=labour,
           base_contribution_list=['base_amount/base_salary',