Replace deprecated datetime.utcnow()

Author: MetRonnie

cylc/flow/wallclock.py

@@ -17,6 +17,7 @@
 
 from calendar import timegm
 from datetime import datetime, timedelta, timezone
+from typing import Optional, Tuple
 
 from metomi.isodatetime.timezone import (
     get_local_time_zone_format, get_local_time_zone, TimeZoneFormatMode)
@@ -74,7 +75,7 @@ def set_utc_mode(mode):
     _FLAGS['utc_mode'] = bool(mode)
 
 
-def now(override_use_utc=None):
+def now(override_use_utc: Optional[bool] = None) -> Tuple[datetime, bool]:
     """Return a current-time datetime.datetime and a UTC timezone flag.
 
     Keyword arguments:
@@ -85,7 +86,7 @@ def now(override_use_utc=None):
 
     """
     if override_use_utc or (override_use_utc is None and _FLAGS['utc_mode']):
-        return datetime.utcnow(), False
+        return datetime.now(timezone.utc), False
     else:
         return datetime.now(), True
 

tests/unit/cycling/test_iso8601.py

@@ -14,7 +14,10 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from datetime import datetime
+from datetime import (
+    datetime,
+    timezone,
+)
 
 import pytest
 from pytest import param
@@ -892,7 +895,7 @@ def test_next_simple_no_now(set_cycling_type):
     point = "next(T00Z)+P1D"
     output = ingest_time(point, my_now)
 
-    current_time = datetime.utcnow()
+    current_time = datetime.now(timezone.utc)
     # my_now is None, but ingest_time will have used a similar time, and
     # the returned value must be after current_time
     output_time = datetime.strptime(output, "%Y%m%dT%H%MZ")

tests/unit/tui/test_util.py

@@ -17,7 +17,8 @@
 
 from datetime import (
     datetime,
-    timedelta
+    timedelta,
+    timezone
 )
 from unittest.mock import Mock
 
@@ -171,7 +172,7 @@ def test_get_task_icon(
     start_time = None
     if start_offset is not None:
         start_time = get_time_string(
-            datetime.utcnow() - timedelta(seconds=start_offset)
+            datetime.now(timezone.utc) - timedelta(seconds=start_offset)
         )
     assert (
         (