diff --git a/.travis.yml b/.travis.yml
index 4cc94fe..f12625e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,7 @@ python:
   - "3.5"
 
 install:
-  - pip install pytest
+  - pip install pytest numpy
   - python setup.py build
   - python setup.py install