added tests and refactored calculate age for vaccination from bday

Author: avshetty1980

lambdas/mns_publisher/src/create_notification.py

@@ -1,7 +1,7 @@
 import json
 import os
 import uuid
-from datetime import datetime
+from datetime import date, datetime
 from typing import Any
 
 from aws_lambda_typing.events.sqs import SQSMessage
@@ -59,22 +59,36 @@ def create_mns_notification(sqs_event: SQSMessage) -> MnsNotificationPayload:
     }
 
 
+def _parse_compact_date(value: str, field_name: str) -> date:
+    if not isinstance(value, str) or not value:
+        raise ValueError(f"{field_name} is required")
+
+    date_part = value[:8]
+    if len(date_part) != 8 or not date_part.isdigit():
+        raise ValueError(f"{field_name} must start with YYYYMMDD")
+
+    try:
+        return datetime.strptime(date_part, "%Y%m%d").date()
+    except ValueError as e:
+        raise ValueError(f"{field_name} must contain a valid date in YYYYMMDD format") from e
+
+
 def calculate_age_at_vaccination(birth_date: str, vaccination_date: str) -> int:
     """
     Calculate patient age in years at time of vaccination.
     Expects dates in format: YYYYMMDD or YYYYMMDDThhmmsszz
     """
-    birth_date_str = birth_date[:8] if len(birth_date) >= 8 else birth_date
-    vacc_date_str = vaccination_date[:8] if len(vaccination_date) >= 8 else vaccination_date
+    date_of_birth = _parse_compact_date(birth_date, "PERSON_DOB")
+    date_of_vaccination = _parse_compact_date(vaccination_date, "DATE_AND_TIME")
 
-    date_of_birth = datetime.strptime(birth_date_str, "%Y%m%d")
-    date_of_vaccination = datetime.strptime(vacc_date_str, "%Y%m%d")
+    if date_of_vaccination < date_of_birth:
+        raise ValueError("DATE_AND_TIME cannot be before PERSON_DOB")
 
-    age_in_year = date_of_vaccination.year - date_of_birth.year
+    age = date_of_vaccination.year - date_of_birth.year
     if (date_of_vaccination.month, date_of_vaccination.day) < (date_of_birth.month, date_of_birth.day):
-        age_in_year -= 1
+        age -= 1
 
-    return age_in_year
+    return age
 
 
 def get_practitioner_details_from_pds(nhs_number: str) -> str | None:

lambdas/mns_publisher/tests/test_create_notification.py

@@ -16,47 +16,41 @@
 class TestCalculateAgeAtVaccination(unittest.TestCase):
     """Tests for age calculation at vaccination time."""
 
-    def test_age_calculation_yyyymmdd_format(self):
-        birth_date = "20040609"
-        vaccination_date = "20260212"
-        age = calculate_age_at_vaccination(birth_date, vaccination_date)
-        self.assertEqual(age, 21)
-
-    def test_age_calculation_with_time(self):
-        birth_date = "20040609T120000"
-        vaccination_date = "20260212T174437"
-        age = calculate_age_at_vaccination(birth_date, vaccination_date)
-        self.assertEqual(age, 21)
-
-    def test_age_calculation_after_birthday(self):
-        birth_date = "20040609"
-        vaccination_date = "20260815"
-        age = calculate_age_at_vaccination(birth_date, vaccination_date)
-        self.assertEqual(age, 22)
-
-    def test_age_calculation_on_birthday(self):
-        birth_date = "20040609"
-        vaccination_date = "20260609"
-        age = calculate_age_at_vaccination(birth_date, vaccination_date)
-        self.assertEqual(age, 22)
-
-    def test_age_calculation_infant(self):
-        birth_date = "20260609"
-        vaccination_date = "20260915"
-        age = calculate_age_at_vaccination(birth_date, vaccination_date)
-        self.assertEqual(age, 0)
-
-    def test_age_calculation_leap_year_birthday(self):
-        birth_date = "20000229"
-        vaccination_date = "20240228"
-        age = calculate_age_at_vaccination(birth_date, vaccination_date)
-        self.assertEqual(age, 23)
-
-    def test_age_calculation_same_day_different_year(self):
-        birth_date = "20000101"
-        vaccination_date = "20250101"
-        age = calculate_age_at_vaccination(birth_date, vaccination_date)
-        self.assertEqual(age, 25)
+    def test_age_calculation_core_cases(self):
+        cases = [
+            ("20040609", "20260212", 21),  # YYYYMMDD format
+            ("20040609", "20260609", 22),  # On birthday
+            ("20040609", "20260815", 22),  # After birthday
+            ("20260609", "20260915", 0),  # Infant
+            ("20040609T120000", "20260212T17443700", 21),  # With time
+            ("20000101", "20250101", 25),  # Same day different year
+            ("20000229", "20240228", 23),  # Leap year birthday
+            ("20000229", "20240229", 24),  # Leap year birthday on leap day
+            ("20000229", "20250228", 24),  # day before; birthday hasn't happened yet
+        ]
+
+        for birth_date, vaccination_date, expected_age in cases:
+            with self.subTest(birth_date=birth_date, vaccination_date=vaccination_date):
+                self.assertEqual(
+                    calculate_age_at_vaccination(birth_date, vaccination_date),
+                    expected_age,
+                )
+
+    def test_rejects_invalid_birth_date_format(self):
+        with self.assertRaisesRegex(ValueError, "PERSON_DOB"):
+            calculate_age_at_vaccination("2004-06-09", "20260212")
+
+    def test_rejects_invalid_vaccination_date_format(self):
+        with self.assertRaisesRegex(ValueError, "DATE_AND_TIME"):
+            calculate_age_at_vaccination("20040609", "2026-02-12")
+
+    def test_rejects_nonexistent_birth_date(self):
+        with self.assertRaisesRegex(ValueError, "PERSON_DOB"):
+            calculate_age_at_vaccination("20040230", "20260212")
+
+    def test_rejects_vaccination_before_birth(self):
+        with self.assertRaisesRegex(ValueError, "cannot be before"):
+            calculate_age_at_vaccination("20260212", "20250212")
 
 
 class TestCreateMnsNotification(unittest.TestCase):