Refactor expected MNS fields population in API tests to handle unset values gracefully. Added checks to prevent overwriting existing context attributes for GP code and patient age, and improved error handling for age calculation to avoid failures during teardown.

Author: Thomas-Boyle

tests/e2e_automation/features/APITests/steps/common_steps.py

@@ -438,8 +438,18 @@ def normalize(value: str) -> str:
 
 
 def populate_expected_mns_fields(context):
-    context.gp_code = get_gp_code_by_nhs_number(context.patient.identifier[0].value)
-    context.patient_age = calculate_age(context.patient.birthDate, context.immunization_object.occurrenceDateTime)
+    if getattr(context, "gp_code", None) is None:
+        context.gp_code = get_gp_code_by_nhs_number(context.patient.identifier[0].value)
+
+    if getattr(context, "patient_age", None) is None:
+        try:
+            context.patient_age = calculate_age(
+                context.patient.birthDate, context.immunization_object.occurrenceDateTime
+            )
+        except ValueError:
+            # Some negative update scenarios intentionally inject invalid DOB values.
+            # Keep patient_age unset here instead of failing teardown validation setup.
+            context.patient_age = None
 
 
 def validate_sqs_message(context, message_body, action):
@@ -483,10 +493,11 @@ def validate_sqs_message(context, message_body, action):
         f"msn event for {action} Source application mismatch: expected {context.supplier_name}, got {message_body.filtering.sourceapplication}",
     )
 
-    check.is_true(
-        message_body.filtering.subjectage == context.patient_age,
-        f"msn event for {action} Age mismatch: expected {context.patient_age}, got {message_body.filtering.subjectage}",
-    )
+    if context.patient_age is not None:
+        check.is_true(
+            message_body.filtering.subjectage == context.patient_age,
+            f"msn event for {action} Age mismatch: expected {context.patient_age}, got {message_body.filtering.subjectage}",
+        )
 
     check.is_true(
         message_body.filtering.immunisationtype == context.vaccine_type.upper(),