magic-removal: Refs #1346 -- Added unit tests for expected behaviour of self referential m2m fields.

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@2380 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/m2m_recursive/models.py

@@ -0,0 +1,92 @@
+"""
+26. Many-to-many relationships between the same two tables
+
+In this example, A Person can have many friends, who are also people. Friendship is a 
+symmetrical relationshiup - if I am your friend, you are my friend.
+
+This test validates that the m2m table will create a mangled name for the m2m table if
+there will be a clash, and tests that symmetry is preserved where appropriate. 
+"""
+
+from django.db import models
+
+class Person(models.Model):
+    name = models.CharField(maxlength=20)
+    friends = models.ManyToManyField('self')
+
+    def __repr__(self):
+        return self.name
+
+API_TESTS = """
+>>> a = Person(name='Anne')
+>>> a.save()
+>>> b = Person(name='Bill')
+>>> b.save()
+>>> c = Person(name='Chuck')
+>>> c.save()
+>>> d = Person(name='David')
+>>> d.save()
+
+# Add some friends in the direction of field definition
+# Anne is friends with Bill and Chuck
+>>> a.friends.add(b,c)
+
+# David is friends with Anne and Chuck - add in reverse direction
+>>> d.friends.add(a,c)
+
+# Who is friends with Anne?
+>>> a.friends.all() 
+[Bill, Chuck, David]
+
+# Who is friends with Bill?
+>>> b.friends.all()
+[Anne]
+
+# Who is friends with Chuck?
+>>> c.friends.all()
+[Anne, David]
+
+# Who is friends with David?
+>>> d.friends.all() 
+[Anne, Chuck]
+
+# Bill is already friends with Anne - add Anne again, but in the reverse direction
+>>> b.friends.add(a)
+
+# Who is friends with Anne?
+>>> a.friends.all() 
+[Bill, Chuck, David]
+
+# Who is friends with Bill?
+>>> b.friends.all()
+[Anne]
+
+# Remove Anne from Bill's friends
+>>> b.friends.remove(a)
+
+# Who is friends with Anne?
+>>> a.friends.all() 
+[Chuck, David]
+
+# Who is friends with Bill?
+>>> b.friends.all()
+[]
+
+# Clear Anne's group of friends
+>>> a.friends.clear()
+
+# Who is friends with Anne?
+>>> a.friends.all() 
+[]
+
+# Reverse relationships should also be gone
+# Who is friends with Chuck?
+>>> c.friends.all()
+[David]
+
+# Who is friends with David?
+>>> d.friends.all() 
+[Chuck]
+
+
+"""