Replace dateutil.tz.tzutc with timezone.utc (#848)

Author: jpinner-lyft

pynamodb/attributes.py

@@ -8,12 +8,13 @@
 import warnings
 from base64 import b64encode, b64decode
 from copy import deepcopy
-from datetime import datetime, timedelta
+from datetime import datetime
+from datetime import timedelta
+from datetime import timezone
 from dateutil.parser import parse
-from dateutil.tz import tzutc
 from inspect import getfullargspec
 from inspect import getmembers
-from typing import Any, Callable, Dict, Generic, List, Mapping, Optional, TypeVar, Type, Union, Set, cast, overload
+from typing import Any, Callable, Dict, Generic, List, Mapping, Optional, TypeVar, Type, Union, Set, overload
 from typing import TYPE_CHECKING
 
 from pynamodb._compat import GenericMeta
@@ -624,7 +625,7 @@ def _normalize(self, value):
             value = calendar.timegm(value.utctimetuple())
         else:
             raise ValueError("TTLAttribute value must be a timedelta or datetime")
-        return datetime.utcfromtimestamp(value).replace(tzinfo=tzutc())
+        return datetime.utcfromtimestamp(value).replace(tzinfo=timezone.utc)
 
     def __set__(self, instance, value):
         """
@@ -645,7 +646,7 @@ def deserialize(self, value):
         Deserializes a timestamp (Unix time) as a UTC datetime.
         """
         timestamp = json.loads(value)
-        return datetime.utcfromtimestamp(timestamp).replace(tzinfo=tzutc())
+        return datetime.utcfromtimestamp(timestamp).replace(tzinfo=timezone.utc)
 
 
 class UTCDateTimeAttribute(Attribute[datetime]):
@@ -659,8 +660,8 @@ def serialize(self, value):
         Takes a datetime object and returns a string
         """
         if value.tzinfo is None:
-            value = value.replace(tzinfo=tzutc())
-        fmt = value.astimezone(tzutc()).strftime(DATETIME_FORMAT)
+            value = value.replace(tzinfo=timezone.utc)
+        fmt = value.astimezone(timezone.utc).strftime(DATETIME_FORMAT)
         return fmt
 
     def deserialize(self, value):
@@ -982,7 +983,7 @@ def _fast_parse_utc_datestring(datestring):
         return datetime(
             _int(datestring[0:4]), _int(datestring[5:7]), _int(datestring[8:10]),
             _int(datestring[11:13]), _int(datestring[14:16]), _int(datestring[17:19]),
-            _int(round(float(datestring[19:-5]) * 1e6)), tzutc()
+            _int(round(float(datestring[19:-5]) * 1e6)), timezone.utc
         )
     except (TypeError, ValueError):
         raise ValueError("Datetime string '{}' does not match format "

tests/test_attributes.py

@@ -2,15 +2,13 @@
 pynamodb attributes tests
 """
 import json
-import time
 
 from base64 import b64encode
 from datetime import datetime
-
 from datetime import timedelta
-from dateutil.tz import tzutc
+from datetime import timezone
 
-from unittest.mock import patch, Mock, call
+from unittest.mock import patch, call
 import pytest
 
 from pynamodb.attributes import (
@@ -25,9 +23,6 @@
 from pynamodb.models import Model
 
 
-UTC = tzutc()
-
-
 class AttributeTestModel(Model):
 
     class Meta:
@@ -148,15 +143,15 @@ def test_utc_date_time_deserialize(self):
         """
         UTCDateTimeAttribute.deserialize
         """
-        tstamp = datetime.now(UTC)
+        tstamp = datetime.now(timezone.utc)
         attr = UTCDateTimeAttribute()
         assert attr.deserialize(tstamp.strftime(DATETIME_FORMAT)) == tstamp
 
     def test_dateutil_parser_fallback(self):
         """
         UTCDateTimeAttribute.deserialize
         """
-        expected_value = datetime(2047, 1, 6, 8, 21, tzinfo=tzutc())
+        expected_value = datetime(2047, 1, 6, 8, 21, tzinfo=timezone.utc)
         attr = UTCDateTimeAttribute()
         assert attr.deserialize('January 6, 2047 at 8:21:00AM UTC') == expected_value
 
@@ -166,7 +161,7 @@ def test_utc_date_time_deserialize_parse_args(self, parse_mock, datetime_mock):
         """
         UTCDateTimeAttribute.deserialize
         """
-        tstamp = datetime.now(UTC)
+        tstamp = datetime.now(timezone.utc)
         attr = UTCDateTimeAttribute()
 
         tstamp_str = tstamp.strftime(DATETIME_FORMAT)
@@ -181,15 +176,15 @@ def test_utc_date_time_serialize(self):
         """
         tstamp = datetime.now()
         attr = UTCDateTimeAttribute()
-        assert attr.serialize(tstamp) == tstamp.replace(tzinfo=UTC).strftime(DATETIME_FORMAT)
+        assert attr.serialize(tstamp) == tstamp.replace(tzinfo=timezone.utc).strftime(DATETIME_FORMAT)
 
     def test__fast_parse_utc_datestring_roundtrips(self):
-        tstamp = datetime.now(UTC)
+        tstamp = datetime.now(timezone.utc)
         tstamp_str = tstamp.strftime(DATETIME_FORMAT)
         assert _fast_parse_utc_datestring(tstamp_str) == tstamp
 
     def test__fast_parse_utc_datestring_no_microseconds(self):
-        expected_value = datetime(2047, 1, 6, 8, 21, tzinfo=tzutc())
+        expected_value = datetime(2047, 1, 6, 8, 21, tzinfo=timezone.utc)
         assert _fast_parse_utc_datestring('2047-01-06T08:21:00.0+0000') == expected_value
 
     @pytest.mark.parametrize(
@@ -497,7 +492,7 @@ def test_timedelta_ttl(self, mock_time):
         mock_time.side_effect = [1559692800]  # 2019-06-05 00:00:00 UTC
         model = AttributeTestModel()
         model.ttl_attr = timedelta(seconds=60)
-        assert model.ttl_attr == datetime(2019, 6, 5, 0, 1, tzinfo=UTC)
+        assert model.ttl_attr == datetime(2019, 6, 5, 0, 1, tzinfo=timezone.utc)
 
     def test_datetime_naive_ttl(self):
         model = AttributeTestModel()
@@ -507,8 +502,8 @@ def test_datetime_naive_ttl(self):
 
     def test_datetime_with_tz_ttl(self):
         model = AttributeTestModel()
-        model.ttl_attr = datetime(2019, 6, 5, 0, 1, tzinfo=UTC)
-        assert model.ttl_attr == datetime(2019, 6, 5, 0, 1, tzinfo=UTC)
+        model.ttl_attr = datetime(2019, 6, 5, 0, 1, tzinfo=timezone.utc)
+        assert model.ttl_attr == datetime(2019, 6, 5, 0, 1, tzinfo=timezone.utc)
 
     def test_ttl_attribute_wrong_type(self):
         with pytest.raises(ValueError, match='TTLAttribute value must be a timedelta or datetime'):
@@ -531,10 +526,10 @@ def test_serialize_deserialize(self, mock_time):
         mock_time.side_effect = [1559692800, 1559692800]  # 2019-06-05 00:00:00 UTC
         model = AttributeTestModel()
         model.ttl_attr = timedelta(minutes=1)
-        assert model.ttl_attr == datetime(2019, 6, 5, 0, 1, tzinfo=UTC)
+        assert model.ttl_attr == datetime(2019, 6, 5, 0, 1, tzinfo=timezone.utc)
         s = TTLAttribute().serialize(model.ttl_attr)
         assert s == '1559692860'
-        assert TTLAttribute().deserialize(s) == datetime(2019, 6, 5, 0, 1, 0, tzinfo=UTC)
+        assert TTLAttribute().deserialize(s) == datetime(2019, 6, 5, 0, 1, 0, tzinfo=timezone.utc)
 
 
 class TestJSONAttribute:

tests/test_model.py

@@ -5,12 +5,13 @@
 import random
 import json
 import copy
-from datetime import datetime, timedelta
+from datetime import datetime
+from datetime import timedelta
+from datetime import timezone
 from unittest import TestCase
 
 from botocore.client import ClientError
 import pytest
-from dateutil.tz import tzutc
 
 from .deep_eq import deep_eq
 from pynamodb.util import snake_to_camel_case
@@ -3300,7 +3301,7 @@ def test_deserialized_with_ttl(self):
         with patch(PATCH_METHOD) as req:
             req.return_value = SIMPLE_MODEL_TABLE_DATA
             m = TTLModel.from_raw_data({'user_name': {'S': 'mock'}, 'my_ttl': {'N': '1546300800'}})
-        assert m.my_ttl == datetime(2019, 1, 1, tzinfo=tzutc())
+        assert m.my_ttl == datetime(2019, 1, 1, tzinfo=timezone.utc)
 
     def test_deserialized_with_invalid_type(self):
         self.assertRaises(AttributeDeserializationError, TTLModel.from_raw_data, {'my_ttl': {'S': '1546300800'}})