Add support for midnight at the end of day

Fix arrow-py#703

Author: ceorcham

arrow/parser.py

@@ -427,6 +427,21 @@ def _build_datetime(parts):
         elif am_pm == "am" and hour == 12:
             hour = 0
 
+        # Support for midnight at the end of day
+        if hour == 24:
+            if parts.get("minute", 0) != 0:
+                raise ParserError("Midnight at the end of day must not contain minutes")
+            if parts.get("second", 0) != 0:
+                raise ParserError("Midnight at the end of day must not contain seconds")
+            if parts.get("microsecond", 0) != 0:
+                raise ParserError(
+                    "Midnight at the end of day must not contain microseconds"
+                )
+            hour = 0
+            day_increment = 1
+        else:
+            day_increment = 0
+
         # account for rounding up to 1000000
         microsecond = parts.get("microsecond", 0)
         if microsecond == 1000000:
@@ -435,7 +450,7 @@ def _build_datetime(parts):
         else:
             second_increment = 0
 
-        increment = timedelta(seconds=second_increment)
+        increment = timedelta(days=day_increment, seconds=second_increment)
 
         return (
             datetime(

tests/parser_tests.py

@@ -586,6 +586,48 @@ def test_parse_DDDD_only(self):
         with self.assertRaises(ParserError):
             self.parser.parse("145", "DDDD")
 
+    def test_parse_HH_24(self):
+        self.assertEqual(
+            self.parser.parse("2019-10-30T24:00:00", "YYYY-MM-DDTHH:mm:ss"),
+            datetime(2019, 10, 31, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse("2019-10-30T24:00", "YYYY-MM-DDTHH:mm"),
+            datetime(2019, 10, 31, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse("2019-10-30T24", "YYYY-MM-DDTHH"),
+            datetime(2019, 10, 31, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse("2019-10-30T24:00:00.0", "YYYY-MM-DDTHH:mm:ss.S"),
+            datetime(2019, 10, 31, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse("2019-10-31T24:00:00", "YYYY-MM-DDTHH:mm:ss"),
+            datetime(2019, 11, 1, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse("2019-12-31T24:00:00", "YYYY-MM-DDTHH:mm:ss"),
+            datetime(2020, 1, 1, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse("2019-12-31T23:59:59.9999999", "YYYY-MM-DDTHH:mm:ss.S"),
+            datetime(2020, 1, 1, 0, 0, 0, 0),
+        )
+
+        with self.assertRaises(ParserError):
+            self.parser.parse("2019-12-31T24:01:00", "YYYY-MM-DDTHH:mm:ss")
+
+        with self.assertRaises(ParserError):
+            self.parser.parse("2019-12-31T24:00:01", "YYYY-MM-DDTHH:mm:ss")
+
+        with self.assertRaises(ParserError):
+            self.parser.parse("2019-12-31T24:00:00.1", "YYYY-MM-DDTHH:mm:ss.S")
+
+        with self.assertRaises(ParserError):
+            self.parser.parse("2019-12-31T24:00:00.999999", "YYYY-MM-DDTHH:mm:ss.S")
+
 
 class DateTimeParserRegexTests(Chai):
     def setUp(self):
@@ -1176,6 +1218,44 @@ def test_iso8601_basic_format(self):
         with self.assertRaises(ParserError):
             self.parser.parse_iso("20180517T1055213Z")
 
+    def test_midnight_end_day(self):
+        self.assertEqual(
+            self.parser.parse_iso("2019-10-30T24:00:00"),
+            datetime(2019, 10, 31, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse_iso("2019-10-30T24:00"),
+            datetime(2019, 10, 31, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse_iso("2019-10-30T24:00:00.0"),
+            datetime(2019, 10, 31, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse_iso("2019-10-31T24:00:00"),
+            datetime(2019, 11, 1, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse_iso("2019-12-31T24:00:00"),
+            datetime(2020, 1, 1, 0, 0, 0, 0),
+        )
+        self.assertEqual(
+            self.parser.parse_iso("2019-12-31T23:59:59.9999999"),
+            datetime(2020, 1, 1, 0, 0, 0, 0),
+        )
+
+        with self.assertRaises(ParserError):
+            self.parser.parse_iso("2019-12-31T24:01:00")
+
+        with self.assertRaises(ParserError):
+            self.parser.parse_iso("2019-12-31T24:00:01")
+
+        with self.assertRaises(ParserError):
+            self.parser.parse_iso("2019-12-31T24:00:00.1")
+
+        with self.assertRaises(ParserError):
+            self.parser.parse_iso("2019-12-31T24:00:00.999999")
+
 
 class TzinfoParserTests(Chai):
     def setUp(self):