DateTime and more: Serialize CrateDB's DateTime types using zone info

Effectively, just add `%z` to the format string passed to `strftime`.

-- https://docs.python.org/3/library/datetime.html#strftime-and-strptime-format-codes

Author: amotl

src/sqlalchemy_cratedb/dialect.py

@@ -117,7 +117,7 @@ def bind_processor(self, dialect):
         def process(value):
             if value is not None:
                 assert isinstance(value, datetime)
-                return value.strftime('%Y-%m-%dT%H:%M:%S.%fZ')
+                return value.strftime('%Y-%m-%dT%H:%M:%S.%f%z')
             return value
         return process
 

tests/datetime_test.py

@@ -51,12 +51,13 @@
 
 
 INPUT_DATE = dt.date(2009, 5, 13)
-INPUT_DATETIME_NOTZ = dt.datetime(2009, 5, 13, 19, 19, 30, 123456)
-INPUT_DATETIME_TZ = dt.datetime(2009, 5, 13, 19, 19, 30, 123456, tzinfo=zoneinfo.ZoneInfo("Europe/Kyiv"))
+INPUT_DATETIME_NOTZ = dt.datetime(2009, 5, 13, 19, 00, 30, 123456)
+INPUT_DATETIME_TZ = dt.datetime(2009, 5, 13, 19, 00, 30, 123456, tzinfo=zoneinfo.ZoneInfo("Europe/Kyiv"))
 OUTPUT_DATE = INPUT_DATE
-OUTPUT_TIME = dt.time(19, 19, 30, 123000)
-OUTPUT_DATETIME_NOTZ = dt.datetime(2009, 5, 13, 19, 19, 30, 123000)
-OUTPUT_DATETIME_TZ = dt.datetime(2009, 5, 13, 19, 19, 30, 123000)
+OUTPUT_TIMETZ_NOTZ = dt.time(19, 00, 30, 123000)
+OUTPUT_TIMETZ_TZ = dt.time(16, 00, 30, 123000)
+OUTPUT_DATETIME_NOTZ = dt.datetime(2009, 5, 13, 19, 00, 30, 123000)
+OUTPUT_DATETIME_TZ = dt.datetime(2009, 5, 13, 16, 00, 30, 123000)
 
 
 @skipIf(SA_VERSION < SA_1_4, "SQLAlchemy 1.3 suddenly has problems with these test cases")
@@ -143,11 +144,11 @@ def test_datetime_notz(session):
     assert result["date"] == OUTPUT_DATE
     assert result["datetime_notz"] == OUTPUT_DATETIME_NOTZ
     assert result["datetime_notz"].tzname() is None
-    assert result["datetime_notz"].timetz() == OUTPUT_TIME
+    assert result["datetime_notz"].timetz() == OUTPUT_TIMETZ_NOTZ
     assert result["datetime_notz"].tzinfo is None
     assert result["datetime_tz"] == OUTPUT_DATETIME_NOTZ
     assert result["datetime_tz"].tzname() is None
-    assert result["datetime_tz"].timetz() == OUTPUT_TIME
+    assert result["datetime_tz"].timetz() == OUTPUT_TIMETZ_NOTZ
     assert result["datetime_tz"].tzinfo is None
 
 
@@ -169,16 +170,17 @@ def test_datetime_tz(session):
     session.execute(sa.text("REFRESH TABLE foobar"))
 
     # Query record.
+    session.expunge(foo_item)
     result = session.execute(sa.select(
         FooBar.name, FooBar.date, FooBar.datetime_notz, FooBar.datetime_tz)).mappings().first()
 
     # Compare outcome.
     assert result["date"] == OUTPUT_DATE
-    assert result["datetime_notz"] == OUTPUT_DATETIME_TZ
+    assert result["datetime_notz"] == OUTPUT_DATETIME_NOTZ
     assert result["datetime_notz"].tzname() is None
-    assert result["datetime_notz"].timetz() == OUTPUT_TIME
+    assert result["datetime_notz"].timetz() == OUTPUT_TIMETZ_NOTZ
     assert result["datetime_notz"].tzinfo is None
     assert result["datetime_tz"] == OUTPUT_DATETIME_TZ
     assert result["datetime_tz"].tzname() is None
-    assert result["datetime_tz"].timetz() == OUTPUT_TIME
+    assert result["datetime_tz"].timetz() == OUTPUT_TIMETZ_TZ
     assert result["datetime_tz"].tzinfo is None

tests/update_test.py

@@ -81,7 +81,7 @@ def test_onupdate_is_triggered(self):
         args = args[1]
         self.assertEqual(expected_stmt, stmt)
         self.assertEqual(40, args[0])
-        dt = datetime.strptime(args[1], '%Y-%m-%dT%H:%M:%S.%fZ')
+        dt = datetime.strptime(args[1], '%Y-%m-%dT%H:%M:%S.%f')
         self.assertIsInstance(dt, datetime)
         self.assertGreater(dt, now)
         self.assertEqual('Arthur', args[2])
@@ -110,6 +110,6 @@ def test_bulk_update(self):
         self.assertEqual(expected_stmt, stmt)
         self.assertEqual('Julia', args[0])
         self.assertEqual({'favorite_book': 'Romeo & Juliet'}, args[1])
-        dt = datetime.strptime(args[2], '%Y-%m-%dT%H:%M:%S.%fZ')
+        dt = datetime.strptime(args[2], '%Y-%m-%dT%H:%M:%S.%f')
         self.assertIsInstance(dt, datetime)
         self.assertGreater(dt, before_update_time)