misc: check SIREN code for ASCII digits (#42808)

tests/test_widgets.py

@@ -737,6 +737,11 @@ def test_wcsextrastringwidget_siren_validation():
     mock_form_submission(req, widget, {'test': 'XXX170130'})
     assert widget.has_error()
 
+    widget = WcsExtraStringWidget('test', value='foo', required=False)
+    widget.field = fakefield
+    mock_form_submission(req, widget, {'test': '443170¹39'})
+    assert widget.has_error()
+
 
 def test_wcsextrastringwidget_siret_validation():
     class FakeField: pass

wcs/qommon/misc.py

@@ -685,7 +685,7 @@ def validate_luhn(string_value, length=None):
         return False
     if length is not None and len(string_value) != length:
         return False
-    if not string_value.isdigit():
+    if not is_ascii_digit(string_value):
         return False
 
     # take all digits counting from the right, double value for digits pair