Invert sign of deposit amount of party

It is less astonishing for the user to see a positive deposit amount when the
party has made a deposit.

issue6558
review37661002

CHANGELOG

@@ -1,3 +1,5 @@
+* Use positive sign for deposit amount of party
+
 Version 4.4.0 - 2017-05-01
 * Bug fixes (see mercurial logs for details)
 

party.py

@@ -50,7 +50,8 @@ class Party:
             cursor.execute(*line.join(account,
                     condition=account.id == line.account
                     ).select(line.party,
-                    Sum(Coalesce(line.debit, 0) - Coalesce(line.credit, 0)),
+                    # Use credit - debit to positive deposit amount
+                    Sum(Coalesce(line.credit, 0) - Coalesce(line.debit, 0)),
                     where=account.active
                     & (account.kind == 'deposit')
                     & party_clause

tests/scenario_deposit.rst

@@ -67,7 +67,7 @@ Check party deposit::
 
     >>> party.reload()
     >>> party.deposit
-    Decimal('-100.00')
+    Decimal('100.00')
 
 Create final invoice::