diff --git a/.drone.yml b/.drone.yml
index 0cadc27..27a7448 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -10,6 +10,7 @@ steps:
     image: python:3.7
     commands:
       - pip install parameterized
+      - pip install numpy
       - python -m unittest discover -v -p *_ut.py
 
   - name: code-analysis