Use relative imports

__init__.py

@@ -1,6 +1,6 @@
 #This file is part of Tryton.  The COPYRIGHT file at the top level of 
 #this repository contains the full copyright notices and license terms.
-from order_point import *
-from product import *
-from purchase_request import *
-from shipment import *
+from .order_point import *
+from .product import *
+from .purchase_request import *
+from .shipment import *

tests/__init__.py

@@ -1,4 +1,4 @@
 #This file is part of Tryton.  The COPYRIGHT file at the top level of
 #this repository contains the full copyright notices and license terms.
 
-from test_stock_supply import suite
+from .test_stock_supply import suite