我有一些Twisted代码可以创建多个Deferreds链。其中一些可能会失败,如果没有errback将它们放回到回调链中。我无法为此代码编写单元测试 - 失败的延迟会导致测试代码完成后测试失败。我如何为这段代码编写一个通过单元测试?预计在正常运行中可能出现故障的每个Deferred应该在链条末端出现错误,并将其放回到回调链上?如何在没有errbacks的情况下对Twisted Deferred错误进行测试?
当DeferredList中Deferred失败时会发生同样的事情,除非我使用consumeErrors创建DeferredList。即使在使用fireOnOneErrback创建DeferredList并给出了将其放回到回调链上的errback时,情况也是如此。除了抑制测试失败和错误日志记录之外,是否还有消耗错误的含义?是否每个Deferred可能失败而没有errback被放置一个DeferredList?
的示例代码示例测试:
from twisted.trial import unittest
from twisted.internet import defer
def get_dl(**kwargs):
"Return a DeferredList with a failure and any kwargs given."
return defer.DeferredList(
[defer.succeed(True), defer.fail(ValueError()), defer.succeed(True)],
**kwargs)
def two_deferreds():
"Create a failing Deferred, and create and return a succeeding Deferred."
d = defer.fail(ValueError())
return defer.succeed(True)
class DeferredChainTest(unittest.TestCase):
def check_success(self, result):
"If we're called, we're on the callback chain."
self.fail()
def check_error(self, failure):
"""
If we're called, we're on the errback chain.
Return to put us back on the callback chain.
"""
return True
def check_error_fail(self, failure):
"""
If we're called, we're on the errback chain.
"""
self.fail()
# This fails after all callbacks and errbacks have been run, with the
# ValueError from the failed defer, even though we're
# not on the errback chain.
def test_plain(self):
"""
Test that a DeferredList without arguments is on the callback chain.
"""
# check_error_fail asserts that we are on the callback chain.
return get_dl().addErrback(self.check_error_fail)
# This fails after all callbacks and errbacks have been run, with the
# ValueError from the failed defer, even though we're
# not on the errback chain.
def test_fire(self):
"""
Test that a DeferredList with fireOnOneErrback errbacks on failure,
and that an errback puts it back on the callback chain.
"""
# check_success asserts that we don't callback.
# check_error_fail asserts that we are on the callback chain.
return get_dl(fireOnOneErrback=True).addCallbacks(
self.check_success, self.check_error).addErrback(
self.check_error_fail)
# This succeeds.
def test_consume(self):
"""
Test that a DeferredList with consumeErrors errbacks on failure,
and that an errback puts it back on the callback chain.
"""
# check_error_fail asserts that we are on the callback chain.
return get_dl(consumeErrors=True).addErrback(self.check_error_fail)
# This succeeds.
def test_fire_consume(self):
"""
Test that a DeferredList with fireOnOneCallback and consumeErrors
errbacks on failure, and that an errback puts it back on the
callback chain.
"""
# check_success asserts that we don't callback.
# check_error_fail asserts that we are on the callback chain.
return get_dl(fireOnOneErrback=True, consumeErrors=True).addCallbacks(
self.check_success, self.check_error).addErrback(
self.check_error_fail)
# This fails after all callbacks and errbacks have been run, with the
# ValueError from the failed defer, even though we're
# not on the errback chain.
def test_two_deferreds(self):
# check_error_fail asserts that we are on the callback chain.
return two_deferreds().addErrback(self.check_error_fail)
很好的答案,但你可能还想提及'--force-gc'。 – Glyph 2010-07-16 03:06:17
好的电话,补充。 – 2010-07-16 18:03:31
这在使用失败实例调用log.err时也会发生,对吗? – Chris 2016-01-24 17:00:37