model: adjust default Edm.DateTime value (#79)

This makes it easier, more likely, to spot dates fixed-up by pyodata.

The new value aligns with Edm.DateTimeOffset.

Author: rettichschnidi

CHANGELOG.md

@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Fix Increased robustness when schema with empty properties is returned
 - Use valid default value for Edm.DateTimeOffset - Reto Schneider
 
+### Changed
+- Adjusted Edm.DateTime default value to January 1, 1753 A.D - Reto Schneider
+
 ## [1.8.0]
 
 ### Fixed

pyodata/v2/model.py

@@ -186,7 +186,7 @@ def _build_types():
             Types.register_type(Typ('Edm.Binary', 'binary\'\'', EdmBinaryTypTraits('(?:binary|X)')))
             Types.register_type(Typ('Edm.Boolean', 'false', EdmBooleanTypTraits()))
             Types.register_type(Typ('Edm.Byte', '0'))
-            Types.register_type(Typ('Edm.DateTime', 'datetime\'2000-01-01T00:00\'', EdmDateTimeTypTraits()))
+            Types.register_type(Typ('Edm.DateTime', 'datetime\'1753-01-01T00:00\'', EdmDateTimeTypTraits()))
             Types.register_type(Typ('Edm.Decimal', '0.0M'))
             Types.register_type(Typ('Edm.Double', '0.0d', EdmFPNumTypTraits.edm_double()))
             Types.register_type(Typ('Edm.Single', '0.0f', EdmFPNumTypTraits.edm_single()))

tests/test_service_v2.py

@@ -2345,6 +2345,28 @@ def test_create_entity_with_naive_datetime(service):
     assert str(e_info.value).startswith('Edm.DateTime accepts only UTC')
 
 
+@responses.activate
+def test_null_datetime(service):
+    """Test default value of DateTime. Default value gets inserted when a property is null"""
+
+    responses.add(
+        responses.GET,
+        f"{service.url}/TemperatureMeasurements",
+        headers={'Content-type': 'application/json'},
+        json={'d': {
+            'results': [
+                {
+                    'Date': None,
+                }
+            ]
+        }},
+        status=200)
+
+    result = service.entity_sets.TemperatureMeasurements.get_entities().execute()
+
+    assert result[0].Date == datetime.datetime(1753, 1, 1, 0, 0, 0, tzinfo=datetime.timezone.utc)
+
+
 @responses.activate
 def test_parsing_of_datetime_before_unix_time(service):
     """Test DateTime handling of time before 1970"""