Install Qt dependencies in the CI environment

.github/workflows/unit-tests.yml

@@ -14,6 +14,8 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         python-version: ["3.12", "3.11", "3.10"]
+    env:
+      DISPLAY: ':99.0'
 
     runs-on: ${{ matrix.os }}
 
@@ -42,6 +44,11 @@ jobs:
           poetry run python -c "from river import datasets; datasets.CreditCard().download(); datasets.Elec2().download(); datasets.SMSSpam().download()"
           poetry run python -c "from river import bandit; bandit.datasets.NewsArticles().download()"
 
+      - uses: tlambert03/setup-qt-libs@v1
+      - name: build "display"
+        run: |
+          /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -screen 0 1920x1200x24 -ac +extension GLX
+
       - name: pytest
         run: |
           poetry run pytest