diff --git a/tests/unit/test_helper.bash b/tests/unit/test_helper.bash
index 2f7ea25a2..16d91f320 100644
--- a/tests/unit/test_helper.bash
+++ b/tests/unit/test_helper.bash
@@ -299,7 +299,7 @@ assert_url() {
 }
 
 assert_urls() {
-  urls="$@"
+  urls=("$@")
   run /bin/bash -c "dokku urls $TEST_APP | xargs"
   echo "output: $output"
   echo "status: $status"