diff -r fd288d118074 -r 3c9066ed557c tests/helpers-testrepo.sh
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/helpers-testrepo.sh	Wed May 11 04:49:27 2016 +0000
@@ -0,0 +1,19 @@
+# The test-repo is a live hg repository which may have evolution
+# markers created, e.g. when a ~/.hgrc enabled evolution.
+#
+# Tests are run using a custom HGRCPATH, which do not
+# enable evolution markers by default.
+#
+# If test-repo includes evolution markers, and we do not
+# enable evolution markers, hg will occasionally complain
+# when it notices them, which disrupts tests resulting in
+# sporadic failures.
+#
+# Since we aren't performing any write operations on the
+# test-repo, there's no harm in telling hg that we support
+# evolution markers, which is what the following lines
+# for the hgrc file do:
+cat >> $HGRCPATH << EOF
+[experimental]
+evolution=createmarkers
+EOF