gistfile1

from twisted.trial.unittest import TestCase
from twisted.internet.defer import Deferred
from twisted.internet import reactor


class TestWhyDoesThisWork(TestCase):
    def test_return_deferred_pass(self):
        d = Deferred()
        d.addCallback(self.assertEqual, 10)
        reactor.callLater(0.1, d.callback, 10)
        return d

    def test_return_deferred_fail(self):
        d = Deferred()
        d.addCallback(self.assertEqual, 10)
        reactor.callLater(0.1, d.callback, 11)
        return d