diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8aeb6fca90b73f5ed000c1fea372517ff2a061f0..91e1df3df82a2eaffa3b44a743d49f2c3081516b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -26,7 +26,7 @@ tests:
     stage: tests
     before_script:
         - apt update
-        - apt install -y libgl1-mesa-glx xvfb graphviz xdg-utils libcairo2-dev libjpeg-dev libgif-dev
+        - apt install -y libgl1-mesa-glx xvfb graphviz libgraphviz-dev xdg-utils libcairo2-dev libjpeg-dev libgif-dev
         - wget -nv https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O /tmp/Miniconda3-latest-Linux-x86_64.sh
         - bash /tmp/Miniconda3-latest-Linux-x86_64.sh -b -p /tmp/miniconda3
         - export PATH=/tmp/miniconda3/bin:$PATH