ci: test with and without UI separately

.github/workflows/check.yml

@@ -13,6 +13,7 @@ jobs:
       matrix:
         python-version: ['3.10']
         os: [macos-latest, ubuntu-latest, windows-latest]
+        deps: ["none", "all"]
     env:
       # Display must be available globally for linux to know where xvfb is
       DISPLAY: :0
@@ -35,16 +36,21 @@ jobs:
       run: |
         # prerequisites
         python -m pip install --upgrade pip wheel
-        python -m pip install coverage flake8
-        # install dependencies
+        python -m pip install coverage flake8 pytest
+        # install base dependencies
         pip install .
-        pip install -r tests/requirements.txt
         # show installed packages
         pip freeze
+    - name: Install extended dependencies
+      if: matrix.deps == "all"
+      run: |
+        pip install .[cli,gui]
+        pip install -r tests/requirements.txt
     - name: Lint with flake8
       run: |
         flake8 --exclude _version.py .
     - name: Start application and print version
+      if: matrix.deps == "all"
       env:
         # Display must be available globally for linux to know where xvfb is
         QT_DEBUG_PLUGINS: 1