Dont break the build if tests only fail on HHVM
diff --git a/.travis.yml b/.travis.yml
index bc13612..27fe3c6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -23,6 +23,10 @@
 
 script: phpunit --coverage-text --configuration tests/travis/$DB.phpunit.xml
 
+matrix:
+  allow_failures:
+    - php: hhvm
+
 branches:
   only:
     - develop