Fix panic in tests

Hopefully

.github/workflows/go.yml

@@ -10,12 +10,17 @@ jobs:
 
   build:
     runs-on: ubuntu-latest
+    env:
+      DISPLAY: ':99.0'
     steps:
     - uses: actions/checkout@v2
     
     - name: Install xorg-dev
       run: sudo apt install xorg-dev
       
+    - name: Xvfb
+      run: Xvfb :99 -screen 0 1024x768x24 > /dev/null 2>&1 &
+
     - name: Set up Go
       uses: actions/setup-go@v2
       with: