lib/testtools/testtools/tests/test_spinner.py

   1 # Copyright (c) 2010 testtools developers. See LICENSE for details.
   2
   3 """Tests for the evil Twisted reactor-spinning we do."""
   4
   5 import os
   6 import signal
   7
   8 from testtools import (
   9     skipIf,
  10     TestCase,
  11     )
  12 from testtools.helpers import try_import
  13 from testtools.matchers import (
  14     Equals,
  15     Is,
  16     MatchesException,
  17     Raises,
  18     )
  19
  20 _spinner = try_import('testtools._spinner')
  21
  22 defer = try_import('twisted.internet.defer')
  23 Failure = try_import('twisted.python.failure.Failure')
  24
  25
  26 class NeedsTwistedTestCase(TestCase):
  27
  28     def setUp(self):
  29         super(NeedsTwistedTestCase, self).setUp()
  30         if defer is None or Failure is None:
  31             self.skipTest("Need Twisted to run")
  32
  33
  34 class TestNotReentrant(NeedsTwistedTestCase):
  35
  36     def test_not_reentrant(self):
  37         # A function decorated as not being re-entrant will raise a
  38         # _spinner.ReentryError if it is called while it is running.
  39         calls = []
  40         @_spinner.not_reentrant
  41         def log_something():
  42             calls.append(None)
  43             if len(calls) < 5:
  44                 log_something()
  45         self.assertThat(
  46             log_something, Raises(MatchesException(_spinner.ReentryError)))
  47         self.assertEqual(1, len(calls))
  48
  49     def test_deeper_stack(self):
  50         calls = []
  51         @_spinner.not_reentrant
  52         def g():
  53             calls.append(None)
  54             if len(calls) < 5:
  55                 f()
  56         @_spinner.not_reentrant
  57         def f():
  58             calls.append(None)
  59             if len(calls) < 5:
  60                 g()
  61         self.assertThat(f, Raises(MatchesException(_spinner.ReentryError)))
  62         self.assertEqual(2, len(calls))
  63
  64
  65 class TestExtractResult(NeedsTwistedTestCase):
  66
  67     def test_not_fired(self):
  68         # _spinner.extract_result raises _spinner.DeferredNotFired if it's
  69         # given a Deferred that has not fired.
  70         self.assertThat(lambda:_spinner.extract_result(defer.Deferred()),
  71             Raises(MatchesException(_spinner.DeferredNotFired)))
  72
  73     def test_success(self):
  74         # _spinner.extract_result returns the value of the Deferred if it has
  75         # fired successfully.
  76         marker = object()
  77         d = defer.succeed(marker)
  78         self.assertThat(_spinner.extract_result(d), Equals(marker))
  79
  80     def test_failure(self):
  81         # _spinner.extract_result raises the failure's exception if it's given
  82         # a Deferred that is failing.
  83         try:
  84             1/0
  85         except ZeroDivisionError:
  86             f = Failure()
  87         d = defer.fail(f)
  88         self.assertThat(lambda:_spinner.extract_result(d),
  89             Raises(MatchesException(ZeroDivisionError)))
  90
  91
  92 class TestTrapUnhandledErrors(NeedsTwistedTestCase):
  93
  94     def test_no_deferreds(self):
  95         marker = object()
  96         result, errors = _spinner.trap_unhandled_errors(lambda: marker)
  97         self.assertEqual([], errors)
  98         self.assertIs(marker, result)
  99
 100     def test_unhandled_error(self):
 101         failures = []
 102         def make_deferred_but_dont_handle():
 103             try:
 104                 1/0
 105             except ZeroDivisionError:
 106                 f = Failure()
 107                 failures.append(f)
 108                 defer.fail(f)
 109         result, errors = _spinner.trap_unhandled_errors(
 110             make_deferred_but_dont_handle)
 111         self.assertIs(None, result)
 112         self.assertEqual(failures, [error.failResult for error in errors])
 113
 114
 115 class TestRunInReactor(NeedsTwistedTestCase):
 116
 117     def make_reactor(self):
 118         from twisted.internet import reactor
 119         return reactor
 120
 121     def make_spinner(self, reactor=None):
 122         if reactor is None:
 123             reactor = self.make_reactor()
 124         return _spinner.Spinner(reactor)
 125
 126     def make_timeout(self):
 127         return 0.01
 128
 129     def test_function_called(self):
 130         # run_in_reactor actually calls the function given to it.
 131         calls = []
 132         marker = object()
 133         self.make_spinner().run(self.make_timeout(), calls.append, marker)
 134         self.assertThat(calls, Equals([marker]))
 135
 136     def test_return_value_returned(self):
 137         # run_in_reactor returns the value returned by the function given to
 138         # it.
 139         marker = object()
 140         result = self.make_spinner().run(self.make_timeout(), lambda: marker)
 141         self.assertThat(result, Is(marker))
 142
 143     def test_exception_reraised(self):
 144         # If the given function raises an error, run_in_reactor re-raises that
 145         # error.
 146         self.assertThat(
 147             lambda:self.make_spinner().run(self.make_timeout(), lambda: 1/0),
 148             Raises(MatchesException(ZeroDivisionError)))
 149
 150     def test_keyword_arguments(self):
 151         # run_in_reactor passes keyword arguments on.
 152         calls = []
 153         function = lambda *a, **kw: calls.extend([a, kw])
 154         self.make_spinner().run(self.make_timeout(), function, foo=42)
 155         self.assertThat(calls, Equals([(), {'foo': 42}]))
 156
 157     def test_not_reentrant(self):
 158         # run_in_reactor raises an error if it is called inside another call
 159         # to run_in_reactor.
 160         spinner = self.make_spinner()
 161         self.assertThat(lambda: spinner.run(
 162             self.make_timeout(), spinner.run, self.make_timeout(),
 163             lambda: None), Raises(MatchesException(_spinner.ReentryError)))
 164
 165     def test_deferred_value_returned(self):
 166         # If the given function returns a Deferred, run_in_reactor returns the
 167         # value in the Deferred at the end of the callback chain.
 168         marker = object()
 169         result = self.make_spinner().run(
 170             self.make_timeout(), lambda: defer.succeed(marker))
 171         self.assertThat(result, Is(marker))
 172
 173     def test_preserve_signal_handler(self):
 174         signals = ['SIGINT', 'SIGTERM', 'SIGCHLD']
 175         signals = filter(
 176             None, (getattr(signal, name, None) for name in signals))
 177         for sig in signals:
 178             self.addCleanup(signal.signal, sig, signal.getsignal(sig))
 179         new_hdlrs = list(lambda *a: None for _ in signals)
 180         for sig, hdlr in zip(signals, new_hdlrs):
 181             signal.signal(sig, hdlr)
 182         spinner = self.make_spinner()
 183         spinner.run(self.make_timeout(), lambda: None)
 184         self.assertEqual(new_hdlrs, map(signal.getsignal, signals))
 185
 186     def test_timeout(self):
 187         # If the function takes too long to run, we raise a
 188         # _spinner.TimeoutError.
 189         timeout = self.make_timeout()
 190         self.assertThat(
 191             lambda:self.make_spinner().run(timeout, lambda: defer.Deferred()),
 192             Raises(MatchesException(_spinner.TimeoutError)))
 193
 194     def test_no_junk_by_default(self):
 195         # If the reactor hasn't spun yet, then there cannot be any junk.
 196         spinner = self.make_spinner()
 197         self.assertThat(spinner.get_junk(), Equals([]))
 198
 199     def test_clean_do_nothing(self):
 200         # If there's nothing going on in the reactor, then clean does nothing
 201         # and returns an empty list.
 202         spinner = self.make_spinner()
 203         result = spinner._clean()
 204         self.assertThat(result, Equals([]))
 205
 206     def test_clean_delayed_call(self):
 207         # If there's a delayed call in the reactor, then clean cancels it and
 208         # returns an empty list.
 209         reactor = self.make_reactor()
 210         spinner = self.make_spinner(reactor)
 211         call = reactor.callLater(10, lambda: None)
 212         results = spinner._clean()
 213         self.assertThat(results, Equals([call]))
 214         self.assertThat(call.active(), Equals(False))
 215
 216     def test_clean_delayed_call_cancelled(self):
 217         # If there's a delayed call that's just been cancelled, then it's no
 218         # longer there.
 219         reactor = self.make_reactor()
 220         spinner = self.make_spinner(reactor)
 221         call = reactor.callLater(10, lambda: None)
 222         call.cancel()
 223         results = spinner._clean()
 224         self.assertThat(results, Equals([]))
 225
 226     def test_clean_selectables(self):
 227         # If there's still a selectable (e.g. a listening socket), then
 228         # clean() removes it from the reactor's registry.
 229         #
 230         # Note that the socket is left open. This emulates a bug in trial.
 231         from twisted.internet.protocol import ServerFactory
 232         reactor = self.make_reactor()
 233         spinner = self.make_spinner(reactor)
 234         port = reactor.listenTCP(0, ServerFactory())
 235         spinner.run(self.make_timeout(), lambda: None)
 236         results = spinner.get_junk()
 237         self.assertThat(results, Equals([port]))
 238
 239     def test_clean_running_threads(self):
 240         import threading
 241         import time
 242         current_threads = list(threading.enumerate())
 243         reactor = self.make_reactor()
 244         timeout = self.make_timeout()
 245         spinner = self.make_spinner(reactor)
 246         spinner.run(timeout, reactor.callInThread, time.sleep, timeout / 2.0)
 247         # Python before 2.5 has a race condition with thread handling where
 248         # join() does not remove threads from enumerate before returning - the
 249         # thread being joined does the removal. This was fixed in Python 2.5
 250         # but we still support 2.4, so we have to workaround the issue.
 251         # http://bugs.python.org/issue1703448.
 252         self.assertThat(
 253             [thread for thread in threading.enumerate() if thread.isAlive()],
 254             Equals(current_threads))
 255
 256     def test_leftover_junk_available(self):
 257         # If 'run' is given a function that leaves the reactor dirty in some
 258         # way, 'run' will clean up the reactor and then store information
 259         # about the junk. This information can be got using get_junk.
 260         from twisted.internet.protocol import ServerFactory
 261         reactor = self.make_reactor()
 262         spinner = self.make_spinner(reactor)
 263         port = spinner.run(
 264             self.make_timeout(), reactor.listenTCP, 0, ServerFactory())
 265         self.assertThat(spinner.get_junk(), Equals([port]))
 266
 267     def test_will_not_run_with_previous_junk(self):
 268         # If 'run' is called and there's still junk in the spinner's junk
 269         # list, then the spinner will refuse to run.
 270         from twisted.internet.protocol import ServerFactory
 271         reactor = self.make_reactor()
 272         spinner = self.make_spinner(reactor)
 273         timeout = self.make_timeout()
 274         spinner.run(timeout, reactor.listenTCP, 0, ServerFactory())
 275         self.assertThat(lambda: spinner.run(timeout, lambda: None),
 276             Raises(MatchesException(_spinner.StaleJunkError)))
 277
 278     def test_clear_junk_clears_previous_junk(self):
 279         # If 'run' is called and there's still junk in the spinner's junk
 280         # list, then the spinner will refuse to run.
 281         from twisted.internet.protocol import ServerFactory
 282         reactor = self.make_reactor()
 283         spinner = self.make_spinner(reactor)
 284         timeout = self.make_timeout()
 285         port = spinner.run(timeout, reactor.listenTCP, 0, ServerFactory())
 286         junk = spinner.clear_junk()
 287         self.assertThat(junk, Equals([port]))
 288         self.assertThat(spinner.get_junk(), Equals([]))
 289
 290     @skipIf(os.name != "posix", "Sending SIGINT with os.kill is posix only")
 291     def test_sigint_raises_no_result_error(self):
 292         # If we get a SIGINT during a run, we raise _spinner.NoResultError.
 293         SIGINT = getattr(signal, 'SIGINT', None)
 294         if not SIGINT:
 295             self.skipTest("SIGINT not available")
 296         reactor = self.make_reactor()
 297         spinner = self.make_spinner(reactor)
 298         timeout = self.make_timeout()
 299         reactor.callLater(timeout, os.kill, os.getpid(), SIGINT)
 300         self.assertThat(lambda:spinner.run(timeout * 5, defer.Deferred),
 301             Raises(MatchesException(_spinner.NoResultError)))
 302         self.assertEqual([], spinner._clean())
 303
 304     @skipIf(os.name != "posix", "Sending SIGINT with os.kill is posix only")
 305     def test_sigint_raises_no_result_error_second_time(self):
 306         # If we get a SIGINT during a run, we raise _spinner.NoResultError.
 307         # This test is exactly the same as test_sigint_raises_no_result_error,
 308         # and exists to make sure we haven't futzed with state.
 309         self.test_sigint_raises_no_result_error()
 310
 311     @skipIf(os.name != "posix", "Sending SIGINT with os.kill is posix only")
 312     def test_fast_sigint_raises_no_result_error(self):
 313         # If we get a SIGINT during a run, we raise _spinner.NoResultError.
 314         SIGINT = getattr(signal, 'SIGINT', None)
 315         if not SIGINT:
 316             self.skipTest("SIGINT not available")
 317         reactor = self.make_reactor()
 318         spinner = self.make_spinner(reactor)
 319         timeout = self.make_timeout()
 320         reactor.callWhenRunning(os.kill, os.getpid(), SIGINT)
 321         self.assertThat(lambda:spinner.run(timeout * 5, defer.Deferred),
 322             Raises(MatchesException(_spinner.NoResultError)))
 323         self.assertEqual([], spinner._clean())
 324
 325     @skipIf(os.name != "posix", "Sending SIGINT with os.kill is posix only")
 326     def test_fast_sigint_raises_no_result_error_second_time(self):
 327         self.test_fast_sigint_raises_no_result_error()
 328
 329
 330 def test_suite():
 331     from unittest import TestLoader
 332     return TestLoader().loadTestsFromName(__name__)