Introduces sorting capabilities within the Redner substitution

Note that we implemented sorting functionality and added unit tests.

The changes include:

• Creation of a new utility file utils/sorting.py implementing sorting functionalities such as : find_field_with_sort_order, parse_fields_with_sort_directions, and sortkey.
• Addition of a new file tests/test_sorting.py containing unit tests for sorting logic.

Associated odoo task

models/redner_substitution.py

@@ -24,6 +24,7 @@ from odoo.exceptions import ValidationError
 from odoo.addons import converter
 
 from ..converter import ImageDataURL, ImageFile
+from ..utils.sorting import find_field_with_sort_order, sortkey
 
 
 class Substitution(models.Model):
@@ -99,9 +100,13 @@ class Substitution(models.Model):
             elif sub.converter == "image-data-url":
                 conv = ImageDataURL(sub.value)
             elif sub.converter == "relation-to-many":
+                # Unpack the result of finding a field with its sort order into
+                # variable names.
+                value, sorted = find_field_with_sort_order(sub.value)
                 conv = converter.RelationToMany(
-                    sub.value,
+                    value,
                     None,
+                    sortkey=sortkey(sorted) if sorted else None,
                     converter=sub.get_children().build_converter(),
                 )
             elif sub.converter == "relation-path":