isInIOThread() returns False when used in TestCases

[sifu]

from twisted.python.threadable import isInIOThread
from twisted.trial import unittest

class IsInIOThread( unittest.TestCase ):

    def test_isInIOThread( self ):
        self.assertEquals( isInIOThread( ), True )

[sifu]

path for scripts/trial.py

[sifu]

this patch fixes it, and doesn't seem to break anything :)

eg: trial on twisted/test: PASSED (skips=31, expectedFailures=7, successes=990)

[exarkun]

Fixing description markup

[exarkun]

The attached patch is very wrong.

This is probably a duplicate of #1614/#3178.

Consider:

from signal import getsignal, SIGCHLD

from twisted.internet import reactor
from twisted.trial import unittest
from twisted.python.threadable import isInIOThread
from twisted.internet.task import deferLater

class ReactorIsNotRunning(unittest.TestCase):
    def test_reactorIsRunning(self):
        print reactor.running
        print getsignal(SIGCHLD)
        print isInIOThread()


class ReactorIsRunning(ReactorIsNotRunning):
    def setUp(self):
        return deferLater(reactor, 0, lambda: None)