'Assigning and removing to/from m2m shouldn\'t generate an m2m signal'

def test_m2m_signals(self):

    b1 = Book(name='Snow    Crash')
    self.get_signal_output(b1.save)
    a1 = Author(name='Neal    Stephenson')
    self.get_signal_output(a1.save)
    self.assertEquals(self.get_signal_output(setattr, b1, 'authors', [a1]), [])
    self.assertEquals(self.get_signal_output(setattr, b1, 'authors', []), [])
