diff --git a/.travis.yml b/.travis.yml
index 66c8f405..1b07da5f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,5 +16,5 @@ deploy:
   script: bash tests/deploy.sh
   on:
     all_branches: true
-    condition: -z $DOCKER_UN
+    condition: -n $DOCKER_UN