Add Unsupported date case to to_lunar_date

Author: wannaphong

pythainlp/util/thai_lunar_date.py

@@ -533,7 +533,7 @@ def to_lunar_date(i_date: date) -> str:
 
     # Check if date is within supported range
     if i_date.year < 1903 or i_date.year > 2460:
-        return "ไม่รองรับ"  # Unsupported date
+        raise NotImplementedError("Unsupported date")  # Unsupported date
 
     # Choose the nearest start date
     c_year = i_date.year - 1

tests/core/test_util.py

@@ -819,6 +819,8 @@ def test_to_lunar_date(self):
         self.assertEqual(to_lunar_date(date(2022, 11, 8)), "ขึ้น 15 ค่ำ เดือน 12")
         self.assertEqual(to_lunar_date(date(2021, 11, 19)), "ขึ้น 15 ค่ำ เดือน 12")
         self.assertEqual(to_lunar_date(date(2020, 10, 31)), "ขึ้น 15 ค่ำ เดือน 12")
+        with self.assertRaises(NotImplementedError):
+            to_lunar_date(date(1885, 9, 7))  # back to the future
 
     def test_th_zodiac(self):
         self.assertEqual(th_zodiac(2024), "มะโรง")