tests: fix units testing for generated item barcodes

The current units testing ensures that the timestamp of the
generated barcode equals the sysdate timestamp. This was incorrect
because the time of the item creation/barcode generation is different
from the sysdate at running the assert command.

Now we test only if the barcode starts with f-.

Co-Authored-by: Aly Badr<aly.badr@rero.ch>

tests/api/test_items_rest.py

@@ -113,25 +113,22 @@ def test_items_post_put_delete(client, document, loc_public_martigny,
     )
     assert res.status_code == 201
     item_barcode = data['metadata']['barcode']
-    assert item_barcode[0:14] == 'f-{}'.format(
-                datetime.now().strftime('%Y%m%d%I%M'))
+    assert item_barcode.startswith('f-')
     # test updating an item with no barcode, keeps the old barcode
     created_item = Item.get_record_by_pid('pid')
     assert created_item.pid == 'pid'
     item_to_update = deepcopy(created_item)
     del item_to_update['barcode']
     updated_item = created_item.update(
         data=item_to_update, dbcommit=True, reindex=True)
-    assert updated_item['barcode'][0:14] == 'f-{}'.format(
-                datetime.now().strftime('%Y%m%d%I%M'))
+    assert updated_item['barcode'].startswith('f-')
 
     # test replacing an item with no barcode, regenerates a new barcode
     item_to_replace = deepcopy(updated_item)
     del item_to_replace['barcode']
     replaced_item = created_item.replace(
         data=item_to_replace, dbcommit=True, reindex=True)
-    assert replaced_item['barcode'][0:14] == 'f-{}'.format(
-                datetime.now().strftime('%Y%m%d%I%M'))
+    assert replaced_item['barcode'].startswith('f-')
 
     # test when item has a dirty barcode
     item_lib_martigny_data['pid'] = '1'