Adding MXSocialSecurityNumberField to local flavor

AUTHORS

@@ -43,6 +43,7 @@ answer newbie questions, and generally made Django that much better:
     ajs <adi@sieker.info>
     alang@bright-green.com
     A S Alam <aalam@users.sf.net>
+    Francisco Albarran Cristobal <pahko.xd@gmail.com>
     Andi Albrecht <albrecht.andi@gmail.com>
     Marty Alchin <gulopine@gamemusic.org>
     Ahmad Alhashemi <trans@ahmadh.com>

django/contrib/localflavor/mx/forms.py

@@ -17,7 +17,6 @@
 document described in the next link:
     http://www.sisi.org.mx/jspsi/documentos/2005/seguimiento/06101/0610100162005_065.doc
 """
-
 RFC_INCONVENIENT_WORDS = [
     u'BUEI', u'BUEY', u'CACA', u'CACO', u'CAGA', u'CAGO', u'CAKA', u'CAKO',
     u'COGE', u'COJA', u'COJE', u'COJI', u'COJO', u'CULO', u'FETO', u'GUEY',
@@ -46,6 +45,7 @@
    u'WUEY',
 ]
 
+
 class MXStateSelect(Select):
     """
     A Select widget that uses a list of Mexican states as its choices.
@@ -105,8 +105,8 @@ class MXRFCField(RegexField):
         http://es.wikipedia.org/wiki/Registro_Federal_de_Contribuyentes_(M%C3%A9xico)
     """
     default_error_messages = {
-        'invalid': _('Enter a valid RFC.'),
-        'invalid_checksum': _('Invalid checksum for RFC.'),
+        'invalid': _(u'Enter a valid RFC.'),
+        'invalid_checksum': _(u'Invalid checksum for RFC.'),
     }
 
     def __init__(self, min_length=9, max_length=13, *args, **kwargs):
@@ -186,7 +186,7 @@ class MXCURPField(RegexField):
         http://www.condusef.gob.mx/index.php/clave-unica-de-registro-de-poblacion-curp
     """
     default_error_messages = {
-        'invalid': _('Enter a valid CURP.'),
+        'invalid': _(u'Enter a valid CURP.'),
         'invalid_checksum': _(u'Invalid checksum for CURP.'),
     }
 
@@ -223,3 +223,53 @@ def _checksum(self, value):
     def _has_inconvenient_word(self, curp):
         first_four = curp[:4]
         return first_four in CURP_INCONVENIENT_WORDS
+
+
+class MXSocialSecurityNumberField(RegexField):
+    """
+    A field that validates a Mexican Social Security Number.
+
+    The Social Security Number is integrated by a juxtaposition of digits
+    following the next pattern:
+
+    =====  =======================================
+    Index  Required numbers
+    =====  =======================================
+    1-2    The number of the branch office where the Social Security Number
+           was designated.
+    3-4    The year of inscription to the Social Security.
+    5-6    The year of birth of the Social Security Number owner.
+    7-10   The progressive number of procedure for the IMSS.
+           (This digit is provided exclusively by the Institute as it regards
+            the Folio number of such procedure).
+    11     The verification digit.
+    """
+    default_error_messages = {
+        'invalid': _(u'Enter a valid Social Security Number.'),
+        'invalid_checksum': _(u'Invalid checksum for Social Security Number.'),
+    }
+
+    def __init__(self, min_length=11, max_length=11, *args, **kwargs):
+        ssn_re = ur'^\d{11}$'
+        ssn_re = re.compile(ssn_re)
+        super(MXSocialSecurityNumberField, self).__init__(ssn_re,
+            min_length=min_length, max_length=max_length, *args, **kwargs)
+
+    def clean(self, value):
+        value = super(MXSocialSecurityNumberField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return u''
+        if value[-1] != self.__checksum(value[:-1]):
+            raise ValidationError(self.default_error_messages['invalid_checksum'])
+        return value
+
+    def __checksum(self, value):
+        multipliers = [1 if i % 2 == 0 else 2 for i in xrange(10)]
+
+        s = [int(v) * m for v, m in zip(value, multipliers)]
+        s = sum(map(int, ''.join(map(str, s))))
+        checksum = 10 - s % 10
+
+        if checksum == 10:
+            return u'0'
+        return unicode(checksum)

django/contrib/localflavor/mx/models.py

@@ -3,7 +3,8 @@
 
 from django.contrib.localflavor.mx.mx_states import STATE_CHOICES
 from django.contrib.localflavor.mx.forms import (MXRFCField as MXRFCFormField,
-    MXZipCodeField as MXZipCodeFormField, MXCURPField as MXCURPFormField)
+    MXZipCodeField as MXZipCodeFormField, MXCURPField as MXCURPFormField,
+    MXSocialSecurityNumberField as MXSocialSecurityNumberFormField)
 
 
 class MXStateField(CharField):
@@ -67,4 +68,21 @@ def __init__(self, *args, **kwargs):
     def formfield(self, **kwargs):
         defaults = {'form_class': MXCURPFormField}
         defaults.update(kwargs)
-        return super(MXCURPField, self).formfield(**defaults)
+        return super(MXCURPField, self).formfield(**defaults)
+
+
+class MXSocialSecurityNumberField(CharField):
+    """
+    A model field that forms represent as a forms.MXSocialSecurityNumberField
+    field and stores the value of a valid Mexican Social Security Number.
+    """
+    description = _("Mexican Social Security Number")
+
+    def __init__(self, *args, **kwargs):
+        kwargs['max_length'] = 11
+        super(MXSocialSecurityNumberField, self).__init__(*args, **kwargs)
+
+    def formfield(self, **kwargs):
+        defaults = {'form_class': MXSocialSecurityNumberFormField}
+        defaults.update(kwargs)
+        return super(MXSocialSecurityNumberField, self).formfield(**defaults)

docs/ref/contrib/localflavor.txt

@@ -842,6 +842,11 @@ Mexico (``mx``)
 
 .. _curp: http://www.condusef.gob.mx/index.php/clave-unica-de-registro-de-poblacion-curp
 
+.. class:: mx.forms.MXSocialSecurityNumberField
+
+   A field that validates a Mexican Social Security Number(NSS) for *Instituto Mexicano del Seguro Social*.
+
+
 .. class:: mx.forms.MXStateSelect
 
     A ``Select`` widget that uses a list of Mexican states as its choices.
@@ -874,6 +879,11 @@ Mexico (``mx``)
     A model field that forms represent as a ``forms.MXCURPField`` field and
     stores the value of a valid Mexican CURP.
 
+.. class:: mx.models.MXSocialSecurityNumberField
+
+    A model field that forms represent as a ``forms.MXSocialSecurityNumberField`` field and
+    stores the eleven-digit Mexican Social Security Number for *Instituto Mexicano del Seguro Social*.
+
 Additionally, a choice tuple is provided in ``django.contrib.localflavor.mx.mx_states``,
 allowing customized model and form fields, and form presentations, for subsets of
 Mexican states abbreviations:

tests/regressiontests/localflavor/mx/models.py

@@ -1,5 +1,6 @@
 from django.contrib.localflavor.mx.models import (
-    MXStateField, MXRFCField, MXCURPField, MXZipCodeField)
+    MXStateField, MXRFCField, MXCURPField, MXZipCodeField,
+    MXSocialSecurityNumberField)
 from django.db import models
 
 
@@ -8,6 +9,7 @@ class MXPersonProfile(models.Model):
     rfc = MXRFCField()
     curp = MXCURPField()
     zip_code = MXZipCodeField()
+    ssn = MXSocialSecurityNumberField()
 
     class Meta:
         app_label = 'localflavor'

tests/regressiontests/localflavor/mx/tests.py

@@ -2,7 +2,7 @@
 from __future__ import absolute_import
 
 from django.contrib.localflavor.mx.forms import (MXZipCodeField, MXRFCField,
-    MXStateSelect, MXCURPField)
+    MXStateSelect, MXCURPField, MXSocialSecurityNumberField)
 from django.test import SimpleTestCase
 
 from .forms import MXPersonProfileForm
@@ -16,6 +16,7 @@ def setUp(self):
             'rfc': 'toma880125kv3',
             'curp': 'toma880125hmnrrn02',
             'zip_code': '58120',
+            'ssn': '53987417457',
         })
 
     def test_get_display_methods(self):
@@ -30,12 +31,14 @@ def test_errors(self):
             'rfc': 'invalid rfc',
             'curp': 'invalid curp',
             'zip_code': 'xxx',
+            'ssn': 'invalid ssn',
         })
         self.assertFalse(form.is_valid())
         self.assertEqual(form.errors['state'], [u'Select a valid choice. Invalid state is not one of the available choices.'])
         self.assertEqual(form.errors['rfc'], [u'Enter a valid RFC.'])
         self.assertEqual(form.errors['curp'], [u'Ensure this value has at least 18 characters (it has 12).', u'Enter a valid CURP.'])
         self.assertEqual(form.errors['zip_code'], [u'Enter a valid zip code in the format XXXXX.'])
+        self.assertEqual(form.errors['ssn'], [u'Enter a valid Social Security Number.'])
 
     def test_field_blank_option(self):
         """Test that the empty option is there."""
@@ -196,3 +199,46 @@ def test_MXCURPField(self):
             'OOMG890727HMNRSR07': error_checksum,
         }
         self.assertFieldOutput(MXCURPField, valid, invalid)
+
+    def test_MXSocialSecurityNumberField(self):
+        error_format = [u'Enter a valid Social Security Number.']
+        error_checksum = [u'Invalid checksum for Social Security Number.']
+        valid = {
+            '53987417457': u'53987417457',
+            '53916912966': u'53916912966',
+            '53986504172': u'53986504172',
+            '17300426925': u'17300426925',
+            '53067407212': u'53067407212',
+            '53018000538': u'53018000538',
+            '10836311612': u'10836311612',
+            '37007910666': u'37007910666',
+            '53055700974': u'53055700974',
+            '17303364941': u'17303364941',
+            '53078528469': u'53078528469',
+        }
+        invalid = {
+            # Invalid format
+            '5398741A457': error_format,
+            '53487G12031': error_format,
+            '530P8028702': error_format,
+            '173004K6925': error_format,
+            '5306T407212': error_format,
+            '53018N00538': error_format,
+            'E0836311612': error_format,
+            '3700U910666': error_format,
+            '530557 0974': error_format,
+            '173033?4941': error_format,
+            '53#88417917': error_format,
+            # Incorrect checksum
+            '53987417451': error_checksum,
+            '53018522942': error_checksum,
+            '53897239693': error_checksum,
+            '01704423244': error_checksum,
+            '53855919735': error_checksum,
+            '53926201296': error_checksum,
+            '53017919037': error_checksum,
+            '53884201248': error_checksum,
+            '42805762629': error_checksum,
+            '53563800130': error_checksum,
+        }
+        self.assertFieldOutput(MXSocialSecurityNumberField, valid, invalid)