misc: add belgian national register number validation (#45039)

tests/test_widgets.py

@@ -1006,6 +1006,36 @@ def test_wcsextrastringwidget_nir_validation():
     assert widget.has_error()
 
 
+def test_wcsextrastringwidget_belgian_nrn_validation():
+    class FakeField:
+        pass
+
+    fakefield = FakeField()
+    fakefield.validation = {'type': 'nrn-be'}
+
+    # regular cases
+    for value in ('85073003328', '17073003384', '40000095579', '00000100364', '40000100133'):
+        widget = WcsExtraStringWidget('test', value='foo', required=False)
+        widget.field = fakefield
+        mock_form_submission(req, widget, {'test': value})
+        assert not widget.has_error()
+
+    # failing cases
+    for value in (
+        '8507300332',  # too short
+        '850730033281',  # too long
+        '8507300332A',  # not just digits
+        '85143003377',  # invalid month
+        '85073203365',  # invalid day
+        '85073003329',  # invalid checksum (<2000)
+        '17073003385',  # invalid checksum (≥2000)
+    ):
+        widget = WcsExtraStringWidget('test', value='foo', required=False)
+        widget.field = fakefield
+        mock_form_submission(req, widget, {'test': value})
+        assert widget.has_error()
+
+
 def test_wcsextrastringwidget_iban_validation():
     class FakeField:
         pass

wcs/qommon/form.py

@@ -1112,6 +1112,14 @@ class ValidationWidget(CompositeWidget):
                     'function': 'validate_nir',
                 },
             ),
+            (
+                'nrn-be',
+                {
+                    'title': _('National register number (Belgium)'),
+                    'error_message': _('Invalid national register number'),
+                    'function': 'validate_belgian_nrn',
+                },
+            ),
             (
                 'iban',
                 {

wcs/qommon/misc.py

@@ -842,6 +842,30 @@ def validate_nir(string_value):
     return int(nir_key) == 97 - int(string_value[:13]) % 97
 
 
+def validate_belgian_nrn(string_value):
+    # https://fr.wikipedia.org/wiki/Numéro_de_registre_national
+    if not string_value:
+        return False
+    if len(string_value) != 11:
+        return False
+    if not is_ascii_digit(string_value):
+        return False
+    _year, month, day, _index, checksum = (
+        string_value[:2],
+        string_value[2:4],
+        string_value[4:6],
+        string_value[6:9],
+        string_value[9:11],
+    )
+    if int(month) > 12:
+        return False
+    if int(day) > 31:
+        return False
+    return (97 - int(string_value[:9]) % 97 == int(checksum)) or (
+        97 - int('2' + string_value[:9]) % 97 == int(checksum)
+    )
+
+
 IBAN_LENGTH = {
     # from https://www.iban.com/structure
     'AD': 24,