diff --git a/tests/issue1210-no-global-cache-in-sources.sh b/tests/issue1210-no-global-cache-in-sources.sh
index c4f0900..7028a13 100644
--- a/tests/issue1210-no-global-cache-in-sources.sh
+++ b/tests/issue1210-no-global-cache-in-sources.sh
@@ -28,5 +28,7 @@
 rm -rf R S
 darcs init  --repo R
 darcs get R S
-not grep "$DARCS_TESTING_CACHE_DIR" S/_darcs/prefs/sources
+if test -n "$DARCS_TESTING_CACHE_DIR"; then
+  not grep "$DARCS_TESTING_CACHE_DIR" S/_darcs/prefs/sources
+fi
 not grep "cache:" S/_darcs/prefs/sources