diff --git a/recommendations/tests/test_solar_pv_recommendations.py b/recommendations/tests/test_solar_pv_recommendations.py
index 87406e49..b16fcc3b 100644
--- a/recommendations/tests/test_solar_pv_recommendations.py
+++ b/recommendations/tests/test_solar_pv_recommendations.py
@@ -26,7 +26,9 @@ class TestSolarPvRecommendations:
             "county": "Huntingdonshire", "property-type": "House", "photo-supply": None
         }
         property_instance_invalid_roof = Property(id=1, address="", postcode="", epc_record=epc_record)
-        property_instance_invalid_roof.roof = {"is_flat": False, "is_pitched": False, "is_roof_room": False}
+        property_instance_invalid_roof.roof = {
+            "is_flat": False, "is_pitched": False, "is_roof_room": False, "thermal_transmittance": None
+        }
         return property_instance_invalid_roof
 
     @pytest.fixture
@@ -36,7 +38,7 @@ class TestSolarPvRecommendations:
         epc_record.prepared_epc = {"photo-supply": "40", "county": "Huntingdonshire",
                                    "property-type": "House"}
         property_instance_has_solar_pv = Property(id=1, address="", postcode="", epc_record=epc_record)
-        property_instance_has_solar_pv.roof = {"is_flat": True}
+        property_instance_has_solar_pv.roof = {"is_flat": True, "thermal_transmittance": None}
         return property_instance_has_solar_pv
 
     @pytest.fixture