Allow assigned move of 0 quantity using view location and delete them

This is needed to be able to ignore assignation of move from a view location,
and to delete them before all moves are set to done.

Closes #12870

modules/stock/move.py

@@ -28,7 +28,8 @@ STATES = {
     'readonly': Eval('state').in_(['cancelled', 'assigned', 'done']),
 }
 LOCATION_DOMAIN = [
-    If(Eval('state').in_(['staging', 'draft', 'cancelled']),
+    If(Eval('state').in_(['staging', 'draft', 'cancelled'])
+        | ((Eval('state') == 'assigned') & ~Eval('quantity')),
         ('type', 'not in', ['warehouse']),
         ('type', 'not in', ['warehouse', 'view'])),
     If(~Eval('state').in_(['done', 'cancelled']),
@@ -927,7 +928,8 @@ class Move(Workflow, ModelSQL, ModelView):
     @classmethod
     def delete(cls, moves):
         for move in moves:
-            if move.state not in {'staging', 'draft', 'cancelled'}:
+            if (move.state not in {'staging', 'draft', 'cancelled'}
+                    and move.quantity):
                 raise AccessError(
                     gettext('stock.msg_move_delete_draft_cancel',
                         move=move.rec_name))

modules/stock/shipment.py

@@ -1537,7 +1537,7 @@ class ShipmentOut(
         Move = pool.get('stock.move')
         Move.delete([
                 m for s in shipments for m in s.inventory_moves
-                if m.state == 'staging'])
+                if m.state == 'staging' or not m.quantity])
         Move.do([m for s in shipments for m in s.inventory_moves])
         Move.draft([m for s in shipments for m in s.outgoing_moves])
         cls._sync_inventory_to_outgoing(shipments, quantity=True)

modules/stock/tests/scenario_stock_shipment_out.rst

@@ -181,7 +181,7 @@ Ignore non assigned moves and pack shipment::
     >>> len(shipment_out.outgoing_moves)
     1
     >>> len(shipment_out.inventory_moves)
-    2
+    1
     >>> shipment_out.inventory_moves[0].state
     'done'
     >>> sum([m.quantity for m in shipment_out.inventory_moves]) == \
@@ -209,7 +209,7 @@ Set the state as Done::
     >>> len(shipment_out.outgoing_moves)
     1
     >>> len(shipment_out.inventory_moves)
-    2
+    1
     >>> shipment_out.inventory_moves[0].state
     'done'
     >>> sum([m.quantity for m in shipment_out.inventory_moves]) == \