test_defer.py   [plain text]

# Twisted, the Framework of Your Internet
# Copyright (C) 2001 Matthew W. Lefkowitz
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of version 2.1 of the GNU Lesser General Public
# License as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


"""
Test cases for defer module.
"""

from __future__ import nested_scopes

from twisted.trial import unittest
from twisted.internet import reactor, defer
from twisted.python import failure, log


class GenericError(Exception): pass

class DeferredTestCase(unittest.TestCase):

    def setUp(self):
        self.callback_results = None
        self.errback_results = None
        self.callback2_results = None

    def _callback(self, *args, **kw):
        self.callback_results = args, kw
        return args[0]

    def _callback2(self, *args, **kw):
        self.callback2_results = args, kw

    def _errback(self, *args, **kw):
        self.errback_results = args, kw

    def testCallbackWithoutArgs(self):
        deferred = defer.Deferred()
        deferred.addCallback(self._callback)
        deferred.callback("hello")
        self.failUnlessEqual(self.errback_results, None)
        self.failUnlessEqual(self.callback_results, (('hello',), {}))

    def testCallbackWithArgs(self):
        deferred = defer.Deferred()
        deferred.addCallback(self._callback, "world")
        deferred.callback("hello")
        self.failUnlessEqual(self.errback_results, None)
        self.failUnlessEqual(self.callback_results, (('hello', 'world'), {}))

    def testCallbackWithKwArgs(self):
        deferred = defer.Deferred()
        deferred.addCallback(self._callback, world="world")
        deferred.callback("hello")
        self.failUnlessEqual(self.errback_results, None)
        self.failUnlessEqual(self.callback_results,
                             (('hello',), {'world': 'world'}))

    def testTwoCallbacks(self):
        deferred = defer.Deferred()
        deferred.addCallback(self._callback)
        deferred.addCallback(self._callback2)
        deferred.callback("hello")
        self.failUnlessEqual(self.errback_results, None)
        self.failUnlessEqual(self.callback_results,
                             (('hello',), {}))
        self.failUnlessEqual(self.callback2_results,
                             (('hello',), {}))

    def testDeferredList(self):
        defr1 = defer.Deferred()
        defr2 = defer.Deferred()
        defr3 = defer.Deferred()
        dl = defer.DeferredList([defr1, defr2, defr3])
        result = []
        def cb(resultList, result=result):
            result.extend(resultList)
        def catch(err):
            return None
        dl.addCallbacks(cb, cb)
        defr1.callback("1")
        defr2.addErrback(catch)
        # "catch" is added to eat the GenericError that will be passed on by
        # the DeferredList's callback on defr2. If left unhandled, the
        # Failure object would cause a log.err() warning about "Unhandled
        # error in Deferred". Twisted's pyunit watches for log.err calls and
        # treats them as failures. So "catch" must eat the error to prevent
        # it from flunking the test.
        defr2.errback(GenericError("2"))
        defr3.callback("3")
        self.failUnlessEqual([result[0],
                    #result[1][1] is now a Failure instead of an Exception
                              (result[1][0], str(result[1][1].value)),
                              result[2]],

                             [(defer.SUCCESS, "1"),
                              (defer.FAILURE, "2"),
                              (defer.SUCCESS, "3")])

    def testEmptyDeferredList(self):
        result = []
        def cb(resultList, result=result):
            result.append(resultList)

        dl = defer.DeferredList([])
        dl.addCallbacks(cb)
        self.failUnlessEqual(result, [[]])

        defr1 = defer.Deferred()
        dl.addDeferred(defr1)
        defr1.callback(1)
        self.failUnlessEqual(result, [[(1, 1)]])

        defr2 = defer.Deferred()
        dl.addDeferred(defr2)
        defr2.callback(2)
        self.failUnlessEqual(result, [[(1, 1), (1, 2)]])

        result[:] = []
        dl = defer.DeferredList([], fireOnOneCallback=1)
        dl.addCallbacks(cb)

        defr1 = defer.Deferred()
        dl.addDeferred(defr1)
        defr1.callback('a')
        self.failUnlessEqual(result, [('a', 0)])

        defr2 = defer.Deferred()
        dl.addDeferred(defr2)
        defr2.callback('b')
        self.failUnlessEqual(result, [('a', 0)])

    def testDeferredListFireOnOneError(self):
        defr1 = defer.Deferred()
        defr2 = defer.Deferred()
        defr3 = defer.Deferred()
        dl = defer.DeferredList([defr1, defr2, defr3], fireOnOneErrback=1)
        result = []
        def catch(err):
            return None
        dl.addErrback(result.append)
        defr1.callback("1")
        defr2.addErrback(catch)
        defr2.errback(GenericError("2"))
        self.failUnlessEqual([str(result[0].value[0].value),
                              str(result[0].value[1])],
                             ["2", "1"])

    def testDeferredListDontConsumeErrors(self):
        d1 = defer.Deferred()
        dl = defer.DeferredList([d1])

        errorTrap = []
        d1.addErrback(errorTrap.append)

        result = []
        dl.addCallback(result.append)
        
        d1.errback(GenericError('Bang'))
        self.failUnlessEqual('Bang', errorTrap[0].value.args[0])
        self.failUnlessEqual(1, len(result))
        self.failUnlessEqual('Bang', result[0][0][1].value.args[0])

    def testDeferredListConsumeErrors(self):
        d1 = defer.Deferred()
        dl = defer.DeferredList([d1], consumeErrors=True)

        errorTrap = []
        d1.addErrback(errorTrap.append)

        result = []
        dl.addCallback(result.append)
        
        d1.errback(GenericError('Bang'))
        self.failUnlessEqual([], errorTrap)
        self.failUnlessEqual(1, len(result))
        self.failUnlessEqual('Bang', result[0][0][1].value.args[0])

    def testDeferredListFireOnOneErrorWithAlreadyFiredDeferreds(self):
        # Create some deferreds, and errback one
        d1 = defer.Deferred()
        d2 = defer.Deferred()
        d1.errback(GenericError('Bang'))
        
        # *Then* build the DeferredList, with fireOnOneErrback=True
        dl = defer.DeferredList([d1, d2], fireOnOneErrback=True)
        result = []
        dl.addErrback(result.append)
        self.failUnlessEqual(1, len(result))

        d1.addErrback(lambda e: None)  # Swallow error

    def testDeferredListWithAlreadyFiredDeferreds(self):
        # Create some deferreds, and err one, call the other
        d1 = defer.Deferred()
        d2 = defer.Deferred()
        d1.errback(GenericError('Bang'))
        d2.callback(2)
        
        # *Then* build the DeferredList
        dl = defer.DeferredList([d1, d2])

        result = []
        dl.addCallback(result.append)

        self.failUnlessEqual(1, len(result))

        d1.addErrback(lambda e: None)  # Swallow error

    def testTimeOut(self):
        d = defer.Deferred()
        d.setTimeout(1.0)
        l = []
        d.addErrback(l.append)
        # Make sure the reactor is shutdown
        d.addBoth(lambda x, r=reactor: r.crash())

        self.assertEquals(l, [])
        reactor.run()
        self.assertEquals(len(l), 1)
        self.assertEquals(l[0].type, defer.TimeoutError)

    def testImmediateSuccess(self):
        l = []
        d = defer.succeed("success")
        d.addCallback(l.append)
        self.assertEquals(l, ["success"])

    def testImmediateSuccess2(self):
        l = []
        d = defer.succeed("success")
        # this is how trial.util.deferredResult works
        d.setTimeout(1.0)
        d.addCallback(l.append)
        self.assertEquals(l, ["success"])

    def testImmediateFailure(self):
        l = []
        d = defer.fail(GenericError("fail"))
        d.addErrback(l.append)
        self.assertEquals(str(l[0].value), "fail")

    def testPausedFailure(self):
        l = []
        d = defer.fail(GenericError("fail"))
        d.pause()
        d.addErrback(l.append)
        self.assertEquals(l, [])
        d.unpause()
        self.assertEquals(str(l[0].value), "fail")

    def testCallbackErrors(self):
        l = []
        d = defer.Deferred().addCallback(lambda _: 1/0).addErrback(l.append)
        d.callback(1)
        self.assert_(isinstance(l[0].value, ZeroDivisionError))
        l = []
        d = defer.Deferred().addCallback(
            lambda _: failure.Failure(ZeroDivisionError())).addErrback(l.append)
        d.callback(1)
        self.assert_(isinstance(l[0].value, ZeroDivisionError))
        
    def testUnpauseBeforeCallback(self):
        d = defer.Deferred()
        d.pause()
        d.addCallback(self._callback)
        d.unpause()

    def testReturnDeferred(self):
        d = defer.Deferred()
        d2 = defer.Deferred()
        d2.pause()
        d.addCallback(lambda r, d2=d2: d2)
        d.addCallback(self._callback)
        d.callback(1)
        assert self.callback_results is None, "Should not have been called yet."
        d2.callback(2)
        assert self.callback_results is None, "Still should not have been called yet."
        d2.unpause()
        assert self.callback_results[0][0] == 2, "Result should have been from second deferred:%s"% (self.callback_results,)

    def testGatherResults(self):
        # test successful list of deferreds
        l = []
        defer.gatherResults([defer.succeed(1), defer.succeed(2)]).addCallback(l.append)
        self.assertEquals(l, [[1, 2]])
        # test failing list of deferreds
        l = []
        dl = [defer.succeed(1), defer.fail(ValueError)]
        defer.gatherResults(dl).addErrback(l.append)
        self.assert_(isinstance(l[0], failure.Failure))
        self.assertEquals(len(l), 1)
        # get rid of error
        dl[1].addErrback(lambda e: 1)
    
    def testMaybeDeferred(self):
        S, E = [], []
        d = defer.maybeDeferred((lambda x: x + 5), 10)
        d.addCallbacks(S.append, E.append)
        self.assertEquals(E, [])
        self.assertEquals(S, [15])
        
        S, E = [], []
        try:
            '10' + 5
        except TypeError, e:
            expected = str(e)
        d = defer.maybeDeferred((lambda x: x + 5), '10')
        d.addCallbacks(S.append, E.append)
        self.assertEquals(S, [])
        self.assertEquals(len(E), 1)
        self.assertEquals(str(E[0].value), expected)
        
        d = defer.Deferred()
        reactor.callLater(0.2, d.callback, 'Success')
        r = unittest.deferredResult(defer.maybeDeferred(lambda: d))
        self.assertEquals(r, 'Success')
        
        d = defer.Deferred()
        reactor.callLater(0.2, d.errback, failure.Failure(RuntimeError()))
        r = unittest.deferredError(defer.maybeDeferred(lambda: d))
        r.trap(RuntimeError)

class AlreadyCalledTestCase(unittest.TestCase):
    def setUp(self):
        defer.Deferred.debug = True
    def tearDown(self):
        defer.Deferred.debug = False

    def _callback(self, *args, **kw):
        pass
    def _errback(self, *args, **kw):
        pass

    def _call_1(self, d):
        d.callback("hello")
    def _call_2(self, d):
        d.callback("twice")
    def _err_1(self, d):
        d.errback(failure.Failure(RuntimeError()))
    def _err_2(self, d):
        d.errback(failure.Failure(RuntimeError()))

    def testAlreadyCalled_CC(self):
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._call_1(d)
        self.failUnlessRaises(defer.AlreadyCalledError, self._call_2, d)

    def testAlreadyCalled_CE(self):
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._call_1(d)
        self.failUnlessRaises(defer.AlreadyCalledError, self._err_2, d)

    def testAlreadyCalled_EE(self):
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._err_1(d)
        self.failUnlessRaises(defer.AlreadyCalledError, self._err_2, d)

    def testAlreadyCalled_EC(self):
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._err_1(d)
        self.failUnlessRaises(defer.AlreadyCalledError, self._call_2, d)


    def _count(self, linetype, func, lines, expected):
        count = 0
        for line in lines:
            if (line.startswith(' %s:' % linetype) and
                line.endswith(' %s' % func)):
                count += 1
        self.failUnless(count == expected)

    def _check(self, e, caller, invoker1, invoker2):
        # make sure the debugging information is vaguely correct
        lines = e.args[0].split("\n")
        # the creator should list the creator (testAlreadyCalledDebug) but not
        # _call_1 or _call_2 or other invokers
        self._count('C', caller, lines, 1)
        self._count('C', '_call_1', lines, 0)
        self._count('C', '_call_2', lines, 0)
        self._count('C', '_err_1', lines, 0)
        self._count('C', '_err_2', lines, 0)
        # invoker should list the first invoker but not the second
        self._count('I', invoker1, lines, 1)
        self._count('I', invoker2, lines, 0)

    def testAlreadyCalledDebug_CC(self):
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._call_1(d)
        try:
            self._call_2(d)
        except defer.AlreadyCalledError, e:
            self._check(e, "testAlreadyCalledDebug_CC", "_call_1", "_call_2")
        else:
            self.fail("second callback failed to raise AlreadyCalledError")

    def testAlreadyCalledDebug_CE(self):
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._call_1(d)
        try:
            self._err_2(d)
        except defer.AlreadyCalledError, e:
            self._check(e, "testAlreadyCalledDebug_CE", "_call_1", "_err_2")
        else:
            self.fail("second errback failed to raise AlreadyCalledError")

    def testAlreadyCalledDebug_EC(self):
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._err_1(d)
        try:
            self._call_2(d)
        except defer.AlreadyCalledError, e:
            self._check(e, "testAlreadyCalledDebug_EC", "_err_1", "_call_2")
        else:
            self.fail("second callback failed to raise AlreadyCalledError")

    def testAlreadyCalledDebug_EE(self):
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._err_1(d)
        try:
            self._err_2(d)
        except defer.AlreadyCalledError, e:
            self._check(e, "testAlreadyCalledDebug_EE", "_err_1", "_err_2")
        else:
            self.fail("second errback failed to raise AlreadyCalledError")

    def testNoDebugging(self):
        defer.Deferred.debug = False
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        self._call_1(d)
        try:
            self._call_2(d)
        except defer.AlreadyCalledError, e:
            self.failIf(e.args)
        else:
            self.fail("second callback failed to raise AlreadyCalledError")


class LogTestCase(unittest.TestCase):

    def setUp(self):
        self.c = []
        log.addObserver(self.c.append)

    def tearDown(self):
        log.removeObserver(self.c.append)
    
    def testErrorLog(self):
        c = self.c
        defer.Deferred().addCallback(lambda x: 1/0).callback(1)
# do you think it is rad to have memory leaks glyph
##        d = defer.Deferred()
##        d.addCallback(lambda x: 1/0)
##        d.callback(1)
##        del d
        c2 = [e for e in c if e["isError"]]
        self.assertEquals(len(c2), 2)
        c2[1]["failure"].trap(ZeroDivisionError)
        log.flushErrors(ZeroDivisionError)


class DeferredTestCaseII(unittest.TestCase):
    def setUp(self):
        self.callbackRan = 0

    def testDeferredListEmpty(self):
        """Testing empty DeferredList."""
        dl = defer.DeferredList([])
        dl.addCallback(self.cb_empty)

    def cb_empty(self, res):
        self.callbackRan = 1
        self.failUnlessEqual([], res)

    def tearDown(self):
        self.failUnless(self.callbackRan, "Callback was never run.")