Update tests/test_scenarios.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: nedseb

tests/test_scenarios.py

@@ -31,7 +31,7 @@ def _print_result(result, test):
 def iter_scenario_tests():
     """Yield (scenario, test) tuples for parametrize."""
     for yaml_file in sorted(SCENARIOS_DIR.glob("*.yaml")):
-        with open(yaml_file) as f:
+        with open(yaml_file, encoding="utf-8") as f:
             scenario = yaml.safe_load(f)
 
         driver = scenario["driver"]