diff --git a/tests/test-worker.t b/tests/test-worker.t
--- a/tests/test-worker.t
+++ b/tests/test-worker.t
@@ -2,6 +2,7 @@ Test UI worker interaction
 
   $ cat > t.py <<EOF
   > from __future__ import absolute_import, print_function
+  > import time
   > from mercurial import (
   >     cmdutil,
   >     error,
@@ -22,6 +23,7 @@ Test UI worker interaction
   >     for arg in args:
   >         ui.status('run\n')
   >         yield 1, arg
+  >     time.sleep(0.1) # easier to trigger killworkers code path
   > functable = {
   >     'abort': abort,
   >     'exc': exc,
@@ -74,20 +76,20 @@ Run tests without worker by forcing a lo
 
 Known exception should be caught, but printed if --traceback is enabled
 
-  $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=2' \
-  > test 100000.0 abort
+  $ 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=2' \
+  $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
   > test 100000.0 abort --traceback 2>&1 | egrep '^(SystemExit|Abort)'
   Abort: known exception
   SystemExit: 255
 
 Traceback must be printed for unknown exceptions
 
-  $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=2' \
+  $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
   > test 100000.0 exc 2>&1 | grep '^Exception'
   Exception: unknown exception