Check rule only if _check_access is set and enforce companies rule

issue4080
review343891009

tests/test_carrier_weight.py

@@ -9,11 +9,11 @@ from trytond.tests.test_tryton import doctest_teardown
 from trytond.tests.test_tryton import doctest_checker
 from trytond.pool import Pool
 
-from trytond.modules.company.tests import CompanyMultiValueTestMixin
+from trytond.modules.company.tests import CompanyTestMixin
 from trytond.modules.currency.tests import create_currency
 
 
-class CarrierWeightTestCase(CompanyMultiValueTestMixin, ModuleTestCase):
+class CarrierWeightTestCase(CompanyTestMixin, ModuleTestCase):
     'Test CarrierWeight module'
     module = 'carrier_weight'
     extras = ['purchase_shipment_cost', 'sale_shipment_cost']