Add descriptor test.

modeltranslation/tests/__init__.py

@@ -227,7 +227,7 @@ class ModeltranslationTest(ModeltranslationTestBase):
         self.failUnless(translator.translator)
 
         # Check that all models are registered for translation
-        self.assertEqual(len(translator.translator.get_registered_models()), 21)
+        self.assertEqual(len(translator.translator.get_registered_models()), 22)
 
         # Try to unregister a model that is not registered
         self.assertRaises(translator.NotRegistered,
@@ -885,6 +885,46 @@ class OtherFieldsTest(ModeltranslationTestBase):
         self.assertEqual(datetime.time(01, 02, 03), inst.time_de)
         self.assertEqual(datetime.time(23, 42, 0), inst.time_en)
 
+    def test_descriptors(self):
+        # Descriptor store ints in database and returns string of 'a' of that length
+        inst = models.DescriptorModel()
+        # Demonstrate desired behaviour
+        inst.normal = 2
+        self.assertEqual('aa', inst.normal)
+        inst.normal = 'abc'
+        self.assertEqual('aaa', inst.normal)
+
+        # Descriptor on translated field works too
+        self.assertEqual('de', get_language())
+        inst.trans = 5
+        self.assertEqual('aaaaa', inst.trans)
+
+        inst.save()
+        db_values = models.DescriptorModel.objects.values('normal', 'trans_en', 'trans_de')[0]
+        self.assertEqual(3, db_values['normal'])
+        self.assertEqual(5, db_values['trans_de'])
+        self.assertEqual(0, db_values['trans_en'])
+
+        # Retrieval from db
+        inst = models.DescriptorModel.objects.all()[0]
+        self.assertEqual('aaa', inst.normal)
+        self.assertEqual('aaaaa', inst.trans)
+        self.assertEqual('aaaaa', inst.trans_de)
+        self.assertEqual('', inst.trans_en)
+
+        # Other language
+        trans_real.activate('en')
+        self.assertEqual('', inst.trans)
+        inst.trans = 'q'
+        self.assertEqual('a', inst.trans)
+        inst.trans_de = 4
+        self.assertEqual('aaaa', inst.trans_de)
+        inst.save()
+        db_values = models.DescriptorModel.objects.values('normal', 'trans_en', 'trans_de')[0]
+        self.assertEqual(3, db_values['normal'])
+        self.assertEqual(4, db_values['trans_de'])
+        self.assertEqual(1, db_values['trans_en'])
+
 
 class ModeltranslationTestRule1(ModeltranslationTestBase):
     """

modeltranslation/tests/models.py

@@ -56,6 +56,50 @@ class OtherFieldsModel(models.Model):
 #    genericip = models.GenericIPAddressField(blank=True, null=True)
 
 
+class FancyDescriptor(object):
+    """
+    Stupid demo descriptor, that store int in database and return string of that length on get.
+    """
+    def __init__(self, field):
+        self.field = field
+
+    def __get__(self, instance, owner):
+        length = instance.__dict__[self.field.name]
+        if length is None:
+            return ''
+        return 'a' * length
+
+    def __set__(self, obj, value):
+        if isinstance(value, int):
+            obj.__dict__[self.field.name] = value
+        elif isinstance(value, basestring):
+            obj.__dict__[self.field.name] = len(value)
+        else:
+            obj.__dict__[self.field.name] = 0
+
+
+class FancyField(models.PositiveIntegerField):
+    def __init__(self, *args, **kwargs):
+        kwargs.setdefault('default', '')
+        super(FancyField, self).__init__(*args, **kwargs)
+
+    def contribute_to_class(self, cls, name):
+        super(FancyField, self).contribute_to_class(cls, name)
+        setattr(cls, self.name, FancyDescriptor(self))
+
+    def pre_save(self, model_instance, add):
+        value = super(FancyField, self).pre_save(model_instance, add)
+        # In this part value should be retrieved using descriptor and be a string
+        assert isinstance(value, basestring)
+        # We put an int to database
+        return len(value)
+
+
+class DescriptorModel(models.Model):
+    normal = FancyField()
+    trans = FancyField()
+
+
 ########## Multitable inheritance testing
 
 class MultitableModelA(models.Model):

modeltranslation/tests/translation.py

@@ -3,8 +3,8 @@ from django.utils.translation import ugettext_lazy
 
 from modeltranslation.translator import translator, TranslationOptions
 from modeltranslation.tests.models import (
-    TestModel, FallbackModel, FallbackModel2, FileFieldsModel, OtherFieldsModel, AbstractModelA,
-    AbstractModelB, Slugged, MetaData, Displayable, Page, RichText, RichTextPage,
+    TestModel, FallbackModel, FallbackModel2, FileFieldsModel, OtherFieldsModel, DescriptorModel,
+    AbstractModelA, AbstractModelB, Slugged, MetaData, Displayable, Page, RichText, RichTextPage,
     MultitableModelA, MultitableModelB, MultitableModelC, ManagerTestModel, CustomManagerTestModel,
     CustomManager2TestModel, GroupFieldsetsModel, NameModel)
 
@@ -45,6 +45,11 @@ class OtherFieldsModelTranslationOptions(TranslationOptions):
 translator.register(OtherFieldsModel, OtherFieldsModelTranslationOptions)
 
 
+class DescriptorModelTranslationOptions(TranslationOptions):
+    fields = ('trans',)
+translator.register(DescriptorModel, DescriptorModelTranslationOptions)
+
+
 ########## Multitable inheritance testing
 
 class MultitableModelATranslationOptions(TranslationOptions):