Get today from ir.date in product cost history test scenario

Since 8d4d6b810c72 the company has a timezone.

Closes #12156

modules/product_cost_history/tests/scenario_product_cost_history.rst

@@ -11,13 +11,13 @@ Imports::
     >>> from trytond.tests.tools import activate_modules
     >>> from trytond.modules.company.tests.tools import create_company, \
     ...     get_company
-    >>> today = dt.date.today()
-    >>> now = dt.datetime.now()
 
 Activate modules::
 
     >>> config = activate_modules('product_cost_history')
 
+    >>> Date = Model.get('ir.date')
+
 Create company::
 
     >>> _ = create_company()
@@ -25,6 +25,9 @@ Create company::
     >>> company.timezone = 'Europe/Madrid'
     >>> company.save()
 
+    >>> today = Date.today(config.context)
+    >>> now = dt.datetime.combine(today, dt.time())
+
 Create product::
 
     >>> ProductUom = Model.get('product.uom')