diff --git a/.github/workflows/python-tests.yml b/.github/workflows/python-tests.yml
index 66e5931..48af192 100644
--- a/.github/workflows/python-tests.yml
+++ b/.github/workflows/python-tests.yml
@@ -24,5 +24,12 @@ jobs:
       - name: Install dependencies
         run: pip install -r requirements.txt
 
+      # The gate's keyboard and layout tests drive real Tk: widget heights and
+      # the focus ring come from the font engine, and no mock can answer what
+      # they ask. Without a display they do not skip -- they fail, which is how
+      # this job stayed red while the tests themselves were fine.
+      - name: Install a virtual X display
+        run: sudo apt-get update && sudo apt-get install -y xvfb
+
       - name: Run tests with coverage
-        run: python -m pytest -v
+        run: xvfb-run -a -s "-screen 0 1600x1200x24" python -m pytest -v