line: Einheit für Anzahl, book: symbol für Asset + tests

book.py

@@ -3,14 +3,14 @@
 # The COPYRIGHT file at the top level of this repository contains the
 # full copyright notices and license terms.
 
-from trytond.model import fields
+from trytond.model import fields, SymbolMixin
 from trytond.exceptions import UserError
 from trytond.pool import PoolMeta
 from trytond.pyson import Eval, Or, Len
 from trytond.modules.cashbook.book import STATES2, DEPENDS2
 
 
-class Book(metaclass=PoolMeta):
+class Book(SymbolMixin, metaclass=PoolMeta):
     __name__ = 'cashbook.book'
 
     asset = fields.Many2One(string='Asset',
@@ -53,6 +53,8 @@ class Book(metaclass=PoolMeta):
                     Len(Eval('lines')) > 0,
                 ),
         }, depends=DEPENDS2+['feature', 'lines', 'asset_uomcat'])
+    symbol = fields.Function(fields.Char(string='Symbol', readonly=True),
+        'on_change_with_symbol')
 
     @fields.depends('asset', 'quantity_uom')
     def on_change_asset(self):
@@ -67,6 +69,15 @@ class Book(metaclass=PoolMeta):
         """
         return 4
 
+    @fields.depends('quantity_uom', 'currency')
+    def on_change_with_symbol(self, name=None):
+        """ get symbol for asset
+        """
+        return '%(currency)s/%(unit)s' % {
+            'currency': getattr(self.currency, 'symbol', '-'),
+            'unit': getattr(self.quantity_uom, 'symbol', '-'),
+            }
+
     @fields.depends('asset', '_parent_asset.uom')
     def on_change_with_asset_uomcat(self, name=None):
         """ get uom-category of asset