--- a/tests/test-run-tests.t	Wed May 11 04:49:27 2016 +0000
+++ b/tests/test-run-tests.t	Wed May 11 16:40:16 2016 +0000
@@ -2,10 +2,7 @@
 
 Avoid interference from actual test env:
 
-  $ unset HGTEST_JOBS
-  $ unset HGTEST_TIMEOUT
-  $ unset HGTEST_PORT
-  $ unset HGTEST_SHELL
+  $ . "$TESTDIR/helper-runtests.sh"
 
 Smoke test with install
 ============