diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 598481b..90a9f8d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -6,6 +6,7 @@ build:
   image: registry.gitlab.gnome.org/jwestman/blueprint-compiler
   stage: build
   script:
+    - black --check --diff blueprintcompiler tests
     - mypy --python-version=3.9 blueprintcompiler
     - coverage run -m unittest
     - coverage report
diff --git a/build-aux/Dockerfile b/build-aux/Dockerfile
index 4b9e0af..27c5a44 100644
--- a/build-aux/Dockerfile
+++ b/build-aux/Dockerfile
@@ -2,7 +2,7 @@ FROM fedora:latest
 
 RUN dnf install -y meson python3-pip gtk4-devel gobject-introspection-devel \
 	libadwaita-devel python3-devel python3-gobject git
-RUN pip3 install furo mypy sphinx coverage
+RUN pip3 install furo mypy sphinx coverage black
 
 # The version on PyPI is very old and doesn't install. Use the upstream package registry instead.
 RUN pip install pythonfuzz --extra-index-url https://gitlab.com/api/v4/projects/19904939/packages/pypi/simple
\ No newline at end of file