created validation function for validating samwat date

bikram/bikram.py

@@ -26,6 +26,8 @@
     dev_digits_re_fragment,
     DEV_TO_ENG_DIGITS_TRANSTABLE as DEV_ENG_TRANS,
     ENG_TO_DEV_DIGITS_TRANSTABLE as ENG_DEV_TRANS,
+    FIRST_AD_YEAR,
+    LAST_AD_YEAR
 )
 
 
@@ -35,6 +37,46 @@
 _PATTERNS_CACHE = {}
 
 
+_FIRST_AD_DATE = {"year": FIRST_AD_YEAR, "month": 1, "day": 1}
+_LAST_BS_DATE = {"year": LAST_AD_YEAR, "month": 12, "day": BS_YEAR_TO_MONTHS[LAST_AD_YEAR][-1]}
+
+
+def _check_int_value(value):
+    if isinstance(value, int) and value > 0:
+        return value
+    else:
+        raise TypeError(
+            'Invalid year, month or day Expected Natural Number "int" got {}: {}'.format(value, type(value).__name__))
+
+
+def _get_max_days_in_month(year, month):
+    try:
+        days = BS_YEAR_TO_MONTHS[year][month]
+        if not days:
+            raise ValueError('Invalid month value')
+        return days
+    except KeyError:
+        raise ValueError(f'Invalid year, supported range is {FIRST_AD_YEAR}-{LAST_AD_YEAR}')
+    except IndexError:
+        raise ValueError('Invalid month value')
+
+
+def _check_date_values(year, month, day):
+    _check_int_value(year)
+    _check_int_value(month)
+    _check_int_value(day)
+
+    if year < FIRST_AD_YEAR or year > LAST_AD_YEAR:
+        raise ValueError(f'Invalid year, supported range is {FIRST_AD_YEAR}-{LAST_AD_YEAR}')
+
+    if month > 12:
+        raise ValueError('Invalid month, supported range is 1-12')
+
+    if day > _get_max_days_in_month(year, month):
+        raise ValueError('Invalid day, supported range is 1-{}'.format(_get_max_days_in_month(year, month)))
+    return year, month, day
+
+
 @total_ordering
 class samwat:
     '''
@@ -107,6 +149,7 @@ class samwat:
     }
 
     def __init__(self, year, month, day, ad=None):
+        year, month, day = _check_date_values(year, month, day)
         self.year = year
         self.month = month
         self.day = day

bikram/constants.py

@@ -181,3 +181,6 @@
     (2089, (None, 30, 32, 31, 32, 31, 30, 30, 30, 29, 30, 30, 30)),
     (2090, (None, 30, 32, 31, 32, 31, 30, 30, 30, 29, 30, 30, 30)),
 ))
+
+FIRST_AD_YEAR = next(iter(BS_YEAR_TO_MONTHS))
+LAST_AD_YEAR = next(reversed(BS_YEAR_TO_MONTHS))

tests/test_samwat.py

@@ -233,3 +233,38 @@ def test_formatters(self):
         for formatstr, formatted_str in formats:
             self.assertEqual(self.bs_date.strftime(formatstr), formatted_str)
             print('PASSED', formatstr, formatted_str)
+
+
+class TestSamwatDateValues(unittest.TestCase):
+    '''
+    Test Year, Month and Day values for samwat class
+    '''
+
+    def setUp(self):
+        self.invalid_values = [
+            {"year": 3001, "month": 1, "day": 1},
+            {"year": 2000, "month": 13, "day": 1},
+            {"year": 2000, "month": 1, "day": 32},
+        ]
+        self.invalid_data_types = [
+
+            {"year": 2000, "month": 4, "day": 21.1},
+            {"year": 2000, "month": 4.34, "day": 13},
+            {"year": "two", "month": 4.34, "day": 13},
+            {"year": 2000, "month": 4, "day": "thirteen"},
+            {"year": 2000, "month": "three", "day": 20},
+            {"year": 2000, "month": 4, "day": 0},
+            {"year": 2000, "month": 0, "day": 13},
+        ]
+
+    def test_samwat_date(self):
+        for invalid_value in self.invalid_values:
+            with self.subTest(invalid_value=invalid_value):
+                with self.assertRaisesRegex(ValueError, 'Invalid'):
+                    samwat(**invalid_value)
+                    print(invalid_value)
+        for invalid_value in self.invalid_data_types:
+            with self.subTest(invalid_value=invalid_value):
+                with self.assertRaisesRegex(TypeError, 'Invalid'):
+                    samwat(**invalid_value)
+                    print('PASSED ', invalid_value)