added condition to skip app testing

Author: lucasimi

tests/test_unit_app.py

@@ -1,3 +1,5 @@
+import sys
+
 import pytest
 from nicegui import ui
 from nicegui.testing import User
@@ -6,6 +8,10 @@
 
 pytest_plugins = ["nicegui.testing.user_plugin"]
 
+pytestmark = pytest.mark.skipif(
+    sys.version_info < (3, 9), reason="NiceGUI requires Python 3.9+"
+)
+
 
 @pytest.mark.module_under_test(_app)
 async def test_run_mapper(user: User) -> None: