diff --git a/tests/unit/test_models/test_full_battery_models/test_base_battery_model.py b/tests/unit/test_models/test_full_battery_models/test_base_battery_model.py
index e35dd2fd7c..d2ec0b4472 100644
--- a/tests/unit/test_models/test_full_battery_models/test_base_battery_model.py
+++ b/tests/unit/test_models/test_full_battery_models/test_base_battery_model.py
@@ -375,7 +375,7 @@ def test_options(self):
             )
         
         # thermal heat of mixing
-        with self.assertRaisesRegex(pybamm.OptionError, "Heat of mixing"):
+        with self.assertRaisesRegex(NotImplementedError, "Heat of mixing"):
             pybamm.BaseBatteryModel(
                 {
                     "heat of mixing": "true",