diff --git a/tests/test-up-local-change b/tests/test-up-local-change
--- a/tests/test-up-local-change
+++ b/tests/test-up-local-change
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+HGMERGE=true; export HGMERGE
+
 set -e
 mkdir r1
 cd r1