diff --git a/.travis.yml b/.travis.yml
index e72730d..c47afbc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,2 +1,2 @@
 language: node_js
-script: make test
\ No newline at end of file
+script: INVARIANT=1 make test
\ No newline at end of file