diff --git a/.travis.yml b/.travis.yml
index db1a2588..75ba367a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,6 +10,7 @@ addons:
     packages:
       - clang-format-5.0
       - g++-6
+      - xsltproc
 
 install:
   - export CC=gcc-6