1 files changed, 106 insertions, 0 deletions
diff --git a/tests/modeltests/field_subclassing/models.py b/tests/modeltests/field_subclassing/models.py
new file mode 100644
index 0000000000..6182266c22
--- /dev/null
+++ b/tests/modeltests/field_subclassing/models.py
@@ -0,0 +1,106 @@
+"""
+Tests for field subclassing.
+"""
+
+from django.db import models
+from django.utils.encoding import force_unicode
+from django.core import serializers
+
+class Small(object):
+    """
+    A simple class to show that non-trivial Python objects can be used as
+    attributes.
+    """
+    def __init__(self, first, second):
+        self.first, self.second = first, second
+
+    def __unicode__(self):
+        return u'%s%s' % (force_unicode(self.first), force_unicode(self.second))
+
+    def __str__(self):
+        return unicode(self).encode('utf-8')
+
+class SmallField(models.Field):
+    """
+    Turns the "Small" class into a Django field. Because of the similarities
+    with normal character fields and the fact that Small.__unicode__ does
+    something sensible, we don't need to implement a lot here.
+    """
+    __metaclass__ = models.SubfieldBase
+
+    def __init__(self, *args, **kwargs):
+        kwargs['max_length'] = 2
+        super(SmallField, self).__init__(*args, **kwargs)
+
+    def get_internal_type(self):
+        return 'CharField'
+
+    def to_python(self, value):
+        if isinstance(value, Small):
+            return value
+        return Small(value[0], value[1])
+
+    def get_db_prep_save(self, value):
+        return unicode(value)
+
+    def get_db_prep_lookup(self, lookup_type, value):
+        if lookup_type == 'exact':
+            return force_unicode(value)
+        if lookup_type == 'in':
+            return [force_unicode(v) for v in value]
+        if lookup_type == 'isnull':
+            return []
+        raise TypeError('Invalid lookup type: %r' % lookup_type)
+
+    def flatten_data(self, follow, obj=None):
+        return {self.attname: force_unicode(self._get_val_from_obj(obj))}
+
+class MyModel(models.Model):
+    name = models.CharField(max_length=10)
+    data = SmallField('small field')
+
+    def __unicode__(self):
+        return force_unicode(self.name)
+
+__test__ = {'API_TESTS': ur"""
+# Creating a model with custom fields is done as per normal.
+>>> s = Small(1, 2)
+>>> print s
+12
+>>> m = MyModel(name='m', data=s)
+>>> m.save()
+
+# Custom fields still have normal field's attributes.
+>>> m._meta.get_field('data').verbose_name
+'small field'
+
+# The m.data attribute has been initialised correctly. It's a Small object.
+>>> m.data.first, m.data.second
+(1, 2)
+
+# The data loads back from the database correctly and 'data' has the right type.
+>>> m1 = MyModel.objects.get(pk=m.pk)
+>>> isinstance(m1.data, Small)
+True
+>>> print m1.data
+12
+
+# We can do normal filtering on the custom field (and will get an error when we
+# use a lookup type that does not make sense).
+>>> s1 = Small(1, 3)
+>>> s2 = Small('a', 'b')
+>>> MyModel.objects.filter(data__in=[s, s1, s2])
+[<MyModel: m>]
+>>> MyModel.objects.filter(data__lt=s)
+Traceback (most recent call last):
+...
+TypeError: Invalid lookup type: 'lt'
+
+# Serialization works, too.
+>>> stream = serializers.serialize("json", MyModel.objects.all())
+>>> stream
+'[{"pk": 1, "model": "field_subclassing.mymodel", "fields": {"data": "12", "name": "m"}}]'
+>>> obj = list(serializers.deserialize("json", stream))[0]
+>>> obj.object == m
+True
+"""}