diff --git a/.github/workflows/pytest.yml b/.github/workflows/pytest.yml
index d36ca75..35535ac 100644
--- a/.github/workflows/pytest.yml
+++ b/.github/workflows/pytest.yml
@@ -22,6 +22,10 @@ jobs:
         uses: actions/setup-python@v3
         with:
           python-version: ${{ matrix.python-version }}
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libegl1 libgl1-mesa-dev libxkbcommon-x11-0
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
diff --git a/examples/ex_gui_2d_maps.py b/examples/ex_gui_2d_maps.py
index 062426d..50d9f58 100644
--- a/examples/ex_gui_2d_maps.py
+++ b/examples/ex_gui_2d_maps.py
@@ -3,11 +3,8 @@
 """
 import sys
 from pathlib import Path
+from PySide6.QtWidgets import QApplication
 import tkinter as tk
-try:
-    from PySide6.QtWidgets import QApplication
-except ImportError:
-    pass
 
 from fitspy.apps.pyside.main import Appli
 from fitspy.apps.tkinter.gui import Appli as Appli_tk
diff --git a/examples/ex_gui_apply_model_to_all_new_spectra.py b/examples/ex_gui_apply_model_to_all_new_spectra.py
index 095fd74..43a4ffb 100644
--- a/examples/ex_gui_apply_model_to_all_new_spectra.py
+++ b/examples/ex_gui_apply_model_to_all_new_spectra.py
@@ -3,11 +3,8 @@
 """
 import sys
 from pathlib import Path
+from PySide6.QtWidgets import QApplication
 import tkinter as tk
-try:
-    from PySide6.QtWidgets import QApplication
-except ImportError:
-    pass
 
 from fitspy.apps.pyside.main import Appli
 from fitspy.apps.tkinter.gui import Appli as Appli_tk
diff --git a/examples/ex_gui_peak_models_in_noise.py b/examples/ex_gui_peak_models_in_noise.py
index 5db9c0d..7d3d21f 100644
--- a/examples/ex_gui_peak_models_in_noise.py
+++ b/examples/ex_gui_peak_models_in_noise.py
@@ -5,11 +5,8 @@
 
 import sys
 from pathlib import Path
+from PySide6.QtWidgets import QApplication
 import tkinter as tk
-try:
-    from PySide6.QtWidgets import QApplication
-except ImportError:
-    pass
 
 from fitspy.apps.pyside.main import Appli
 from fitspy.apps.tkinter.gui import Appli as Appli_tk
diff --git a/examples/ex_gui_users_defined_models_2d_map.py b/examples/ex_gui_users_defined_models_2d_map.py
index 3146ab3..a11d839 100644
--- a/examples/ex_gui_users_defined_models_2d_map.py
+++ b/examples/ex_gui_users_defined_models_2d_map.py
@@ -3,11 +3,8 @@
 """
 import sys
 from pathlib import Path
+from PySide6.QtWidgets import QApplication
 import tkinter as tk
-try:
-    from PySide6.QtWidgets import QApplication
-except ImportError:
-    pass
 
 from fitspy.apps.pyside.main import Appli
 from fitspy.apps.tkinter.gui import Appli as Appli_tk