diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 79df258514e1edb62788079667941dee9ef38f13..100c8090445b6b2681c8748516c5fa36cad46227 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,7 +1,7 @@
 run_tests:
   image: "python:$VERSION"
   script:
-    - apt install graphviz
+    - apt update && apt install graphviz
     - pip install -e .[dev]
     - export PYTHONPATH="$(pwd)"
     - coverage run --source . run_tests.py