Django test class for asserting the connection of a receiver to a given signal

my_test.py

from django.test import TestCase


class ReceiverConnectionTestCase(TestCase):
    """TestCase that allows asserting that a given receiver is connected to a signal.
    
    Important: this will work correctly providing you:
        1. Do not import or patch anything in the module containing the receiver in any django.test.TestCase.
        2. Do not import (except in the context of a method) the module containing the receiver in any test module.
    
    This is because as soon as you import/patch, the receiver will be connected by your test and will be connected
    for the entire test suite run.
    
    If you want to test the behaviour of the receiver, you may do this providing it is a unittest.TestCase, and there
    is no import from the receiver module in that test module.
    
    Usage:
    
        # myapp/receivers.py
        from django.dispatch import receiver
        from apples.signals import apple_eaten
        from apples.models import Apple
        
        @receiver(apple_eaten, sender=Apple)
        def my_receiver(sender, **kwargs):
            pass
       
    
        # tests/integration_tests.py
        from apples.signals import apple_eaten
        from apples.models import Apple
        
        class TestMyReceiverConnection(ReceiverConnectionTestCase):
            def test_connection(self):
                self.assert_receiver_is_connected('myapp.receivers.my_receiver', signal=apple_eaten, sender=Apple)
    
    """
    def assert_receiver_is_connected(self, receiver_string, signal, sender):
        receivers = signal._live_receivers(sender)
        receiver_strings = ["{}.{}".format(r.__module__, r.__name__) for r in receivers]
        if receiver_string not in receiver_strings:
            raise AssertionError('{} is not connected to signal.'.format(receiver_string))

For more details see my talk slides: http://slides.com/davidseddon/signals