Fix sign of the amount to pay on line

issue2746
review464003

statement.py

@@ -262,7 +262,9 @@ class Statement(Workflow, ModelSQL, ModelView):
                         else:
                             res['lines']['update'].append({
                                 'id': line['id'],
-                                'amount': amount_to_pay,
+                                'amount': (amount_to_pay
+                                        if line['amount'] >= 0
+                                        else -amount_to_pay),
                                 })
                             res['lines'].setdefault('add', [])
                             vals = line.copy()

tests/scenario_account_statement.rst

@@ -265,11 +265,16 @@ Paid 50 to supplier::
     >>> statement_line = StatementLine()
     >>> statement.lines.append(statement_line)
     >>> statement_line.date = today
-    >>> statement_line.amount = Decimal('-50')
+    >>> statement_line.amount = Decimal('-60')
     >>> statement_line.party = supplier
     >>> statement_line.account == payable
     True
     >>> statement_line.invoice = supplier_invoice
+    >>> statement_line.amount == Decimal('-50')
+    True
+    >>> statement_line = statement.lines.pop()
+    >>> statement_line.amount == Decimal('-10')
+    True
 
     >>> statement.save()