def test_nonDestructiveDeferredCallback(self):
"""
Verify the use of non-destructive deferred chaining: a chained deferred is
created with a callback that returns nothing - verify that a second
callback on the original deferred receives the original value.
"""
x = Deferred()
chained = []
notchained = []
def ccb(val):
chained.append(val)
return 3
ndc = _ndchain(x).addCallback(ccb)
def ucb(val):
notchained.append(val)
return 4
x.addCallback(ucb)
x.callback(2)
self.assertEquals(notchained, [2])
self.assertEquals(chained, [2])
self.assertEquals(ndc.result, 3)
self.assertEquals(x.result, 4)
def test_nonDestructiveDeferredAbuse(self):
"""
Verify that the non-destructive deferred will not break its callback,
even if its result is (incorrectly) called back externally.
"""
x = Deferred()
boom = _ndchain(x)
boom.callback(1)
l = []
x.addCallback(lambda n : (l.append(n) or 9))
x.callback(7)
self.assertEquals(l, [7])
self.assertEquals(x.result, 9)
self.assertEquals(len(self.flushLoggedErrors(AlreadyCalledError)), 1)
def test_nonDestructiveDeferredAbuse(self):
"""
Verify that the non-destructive deferred will not break its callback,
even if its result is (incorrectly) called back externally.
"""
x = Deferred()
boom = _ndchain(x)
boom.callback(1)
l = []
x.addCallback(lambda n: (l.append(n) or 9))
x.callback(7)
self.assertEquals(l, [7])
self.assertEquals(x.result, 9)
self.assertEquals(len(self.flushLoggedErrors(AlreadyCalledError)), 1)
def test_nonDestructiveDeferredCallback(self):
"""
Verify the use of non-destructive deferred chaining: a chained deferred is
created with a callback that returns nothing - verify that a second
callback on the original deferred receives the original value.
"""
x = Deferred()
chained = []
notchained = []
def ccb(val):
chained.append(val)
return 3
ndc =_ndchain(x).addCallback(ccb)
def ucb(val):
notchained.append(val)
return 4
x.addCallback(ucb)
x.callback(2)
self.assertEquals(notchained, [2])
self.assertEquals(chained, [2])
self.assertEquals(ndc.result, 3)
self.assertEquals(x.result, 4)
