fix test

tests/openlp_core/ui/test_themeform.py

@@ -23,6 +23,7 @@
 Interface tests to test the ThemeWizard class and related methods.
 """
 from unittest import TestCase
+from unittest.mock import patch
 
 from openlp.core.common.registry import Registry
 from openlp.core.ui.themeform import ThemeForm
@@ -39,7 +40,8 @@ class TestThemeManager(TestCase, TestMixin):
         """
         Registry.create()
 
-    def test_create_theme_wizard(self):
+    @patch('openlp.core.display.window.QtWidgets.QVBoxLayout')
+    def test_create_theme_wizard(self, mocked_qvboxlayout):
         """
         Test creating a ThemeForm instance
         """