py3: add alternate output on Python 3

This is basically the same deal as D5806. Python 3's exception
printing output is different.

We had to tweak the regular expression to match appropriately,
hence the added line of output.

Differential Revision: https://phab.mercurial-scm.org/D5807

tests/test-worker.t

@@ -1,128 +1,130 b''
 Test UI worker interaction
 
   $ cat > t.py <<EOF
   > from __future__ import absolute_import, print_function
   > import time
   > from mercurial import (
   >     error,
   >     registrar,
   >     ui as uimod,
   >     worker,
   > )
   > def abort(ui, args):
   >     if args[0] == 0:
   >         # by first worker for test stability
   >         raise error.Abort(b'known exception')
   >     return runme(ui, [])
   > def exc(ui, args):
   >     if args[0] == 0:
   >         # by first worker for test stability
   >         raise Exception('unknown exception')
   >     return runme(ui, [])
   > def runme(ui, args):
   >     for arg in args:
   >         ui.status(b'run\n')
   >         yield 1, arg
   >     time.sleep(0.1) # easier to trigger killworkers code path
   > functable = {
   >     b'abort': abort,
   >     b'exc': exc,
   >     b'runme': runme,
   > }
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > @command(b'test', [], b'hg test [COST] [FUNC]')
   > def t(ui, repo, cost=1.0, func=b'runme'):
   >     cost = float(cost)
   >     func = functable[func]
   >     ui.status(b'start\n')
   >     runs = worker.worker(ui, cost, func, (ui,), range(8))
   >     for n, i in runs:
   >         pass
   >     ui.status(b'done\n')
   > EOF
   $ abspath=`pwd`/t.py
   $ hg init
 
 Run tests with worker enable by forcing a heigh cost
 
   $ hg --config "extensions.t=$abspath" test 100000.0
   start
   run
   run
   run
   run
   run
   run
   run
   run
   done
 
 Run tests without worker by forcing a low cost
 
   $ hg --config "extensions.t=$abspath" test 0.0000001
   start
   run
   run
   run
   run
   run
   run
   run
   run
   done
 
 #if no-windows
 
 Known exception should be caught, but printed if --traceback is enabled
 
   $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
   > test 100000.0 abort 2>&1
   start
   abort: known exception
   [255]
 
   $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
-  > test 100000.0 abort --traceback 2>&1 | egrep '^(SystemExit|Abort)'
-  Abort: known exception
+  > test 100000.0 abort --traceback 2>&1 | egrep '(SystemExit|Abort)'
+      raise error.Abort(b'known exception')
+  mercurial.error.Abort: b'known exception' (py3 !)
+  Abort: known exception (no-py3 !)
   SystemExit: 255
 
 Traceback must be printed for unknown exceptions
 
   $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
   > test 100000.0 exc 2>&1 | grep '^Exception'
   Exception: unknown exception
 
 Workers should not do cleanups in all cases
 
   $ cat > $TESTTMP/detectcleanup.py <<EOF
   > from __future__ import absolute_import
   > import atexit
   > import os
   > import time
   > oldfork = os.fork
   > count = 0
   > parentpid = os.getpid()
   > def delayedfork():
   >     global count
   >     count += 1
   >     pid = oldfork()
   >     # make it easier to test SIGTERM hitting other workers when they have
   >     # not set up error handling yet.
   >     if count > 1 and pid == 0:
   >         time.sleep(0.1)
   >     return pid
   > os.fork = delayedfork
   > def cleanup():
   >     if os.getpid() != parentpid:
   >         os.write(1, 'should never happen\n')
   > atexit.register(cleanup)
   > EOF
 
   $ hg --config "extensions.t=$abspath" --config worker.numcpus=8 --config \
   > "extensions.d=$TESTTMP/detectcleanup.py" test 100000 abort
   start
   abort: known exception
   [255]
 
 #endif