diff --git a/.travis.yml b/.travis.yml
index 8320624..24f917b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,6 +15,7 @@ before_install:
 
 install:
   - luarocks install busted
+  - luarocks install lua-cjson
   - luarocks install luacov
   - luarocks install luacov-coveralls