Added one_to_one model unit test/example

git-svn-id: http://code.djangoproject.com/svn/django/trunk@355 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/testapp/models/__init__.py

@@ -1 +1 @@
-__all__ = ['basic', 'repr', 'custom_methods', 'many_to_one', 'many_to_many', 'ordering', 'lookup', 'get_latest', 'm2m_intermediary']
+__all__ = ['basic', 'repr', 'custom_methods', 'many_to_one', 'many_to_many', 'ordering', 'lookup', 'get_latest', 'm2m_intermediary', 'one_to_one']

tests/testapp/models/one_to_one.py

@@ -0,0 +1,63 @@
+"""
+10. One-to-one relationships
+
+To define a many-to-one relationship, use OneToOneField().
+
+In this example, a Place optionally can be a Restaurant.
+"""
+
+from django.core import meta
+
+class Place(meta.Model):
+    fields = (
+        meta.CharField('name', maxlength=50),
+        meta.CharField('address', maxlength=80),
+    )
+
+    def __repr__(self):
+        return "%s the place" % self.name
+
+class Restaurant(meta.Model):
+    fields = (
+        meta.OneToOneField(Place),
+        meta.BooleanField('serves_hot_dogs'),
+        meta.BooleanField('serves_pizza'),
+    )
+
+    def __repr__(self):
+        return "%s the restaurant" % self.get_place().name
+
+API_TESTS = """
+# Create a couple of Places.
+>>> p1 = places.Place(id=None, name='Demon Dogs', address='944 W. Fullerton')
+>>> p1.save()
+>>> p2 = places.Place(id=None, name='Ace Hardware', address='1013 N. Ashland')
+>>> p2.save()
+
+# Create a Restaurant. Pass the ID of the "parent" object as this object's ID.
+>>> r = restaurants.Restaurant(id=p1.id, serves_hot_dogs=True, serves_pizza=False)
+>>> r.save()
+
+# A Restaurant can access its place.
+>>> r.get_place()
+Demon Dogs the place
+
+# A Place can access its restaurant, if available.
+>>> p1.get_restaurant()
+Demon Dogs the restaurant
+
+# p2 doesn't have an associated restaurant.
+>>> p2.get_restaurant()
+Traceback (most recent call last):
+    ...
+RestaurantDoesNotExist: Restaurant does not exist for {'id__exact': 2L}
+
+# restaurants.get_list() just returns the Restaurants, not the Places.
+>>> restaurants.get_list()
+[Demon Dogs the restaurant]
+
+# places.get_list() returns all Places, regardless of whether they have
+# Restaurants.
+>>> places.get_list(order_by=['name'])
+[Ace Hardware the place, Demon Dogs the place]
+"""