Fixed #1661 -- Added logic for string-form model references in the 'to'...

class OneToOneField(RelatedField, IntegerField):

    def __init__(self, to, to_field=None, **kwargs):

        kwargs['verbose_name'] = kwargs.get('verbose_name', '')

        try:

            to_name = to._meta.object_name.lower()

        except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT

            assert isinstance(to, basestring), "OneToOneField(%r) is invalid. First parameter to OneToOneField must be either a model, a model name, or the string %r" % (to, RECURSIVE_RELATIONSHIP_CONSTANT)

        else:

            to_field = to_field or to._meta.pk.name

        kwargs['verbose_name'] = kwargs.get('verbose_name', '')

        if kwargs.has_key('edit_inline_type'):

            import warnings

    def __str__(self):

        return "Whiz %s" % self.name

class Child(models.Model):

    parent = models.OneToOneField('Base')

    name = models.CharField(maxlength = 50)

    def __str__(self):

        return "Child %s" % self.name

class Base(models.Model):

    name = models.CharField(maxlength = 50)

    def __str__(self):

        return "Base %s" % self.name

API_TESTS = """

# Regression test for #1662: Check that string form referencing of models works, both as

# pre and post reference

# Regression test for #1661 and #1662: Check that string form referencing of models works, 

# both as pre and post reference, on all RelatedField types.

>>> f1 = Foo(name="Foo1")

>>> f1.save()

>>> b1.back

<Foo: Foo Foo1>

>>> base1 = Base(name="Base1")

>>> base1.save()

>>> child1 = Child(name="Child1", parent=base1)

>>> child1.save()

>>> child1.parent

<Base: Base Base1>

"""