--- a/tests/test-run-tests.t Wed Apr 04 17:29:02 2018 -0700
+++ b/tests/test-run-tests.t Wed Apr 04 17:33:59 2018 -0700
@@ -558,7 +558,12 @@
Verify that we can try other ports
===================================
- $ hg init inuse
+
+Extensions aren't inherited by the invoked run-tests.py. An extension
+introducing a repository requirement could cause this to fail. So we force
+HGRCPATH to get a clean environment.
+
+ $ HGRCPATH= hg init inuse
$ hg serve -R inuse -p $HGPORT -d --pid-file=blocks.pid
$ cat blocks.pid >> $DAEMON_PIDS
$ cat > test-serve-inuse.t <<EOF