Test to demonstrate failing iso datetime parsing for a resource

[tomeksabala]

I have encountered this bug while trying to call action resource_update with the field:

'last_modified': '2021-07-02T07:11:03.519Z'

which results in:

{
    "success": false,
    "error": {
        "last_modified": [
            "Date format incorrect"
        ],
        "__type": "Validation Error"
    }
}

I get success behavior if I remove the tz info from date string "Z".

To easily demonstrate the behavior I've created a failing test case scenario.

=================================== FAILURES ===================================
____________ TestDateTimes.test_datetime_with_tz_field_in_resource _____________

self = <ckanext.scheming.tests.test_validation.TestDateTimes object at 0x7f2802486650>

    def test_datetime_with_tz_field_in_resource(self):
        lc = LocalCKAN()
        lc.action.package_create(
            type="test-schema",
            name="derf_datetime_2",
            resources=[
                {
                    "url": "http://example.com/camel.txt",
                    "camels_in_photo": 2,
>                   "datetime": "2015-01-01T12:35:00Z",
                }
            ],
        )

/usr/lib/adx/ckanext-scheming/ckanext/scheming/tests/test_validation.py:324: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
../../local/lib/python2.7/site-packages/ckanapi/common.py:51: in action
    return self._ckan.call_action(name, data_dict=kwargs)
../../local/lib/python2.7/site-packages/ckanapi/localckan.py:71: in call_action
    return self._get_action(action)(context, data_dict)
ckan/logic/__init__.py:477: in wrapped
    result = _action(context, data_dict, **kw)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

context = {'__auth_audit': [], '__auth_user_obj_checked': True, 'auth_user_obj': <User id=73ac7c2b-f39a-4d49-9733-28fb38f95fb1 n...ne plugin_extras=None>, 'model': <module 'ckan.model' from '/usr/lib/ckan/venv/src/ckan/ckan/model/__init__.pyc'>, ...}
data_dict = {'name': 'derf_datetime_2', 'resources': [{'camels_in_photo': 2, 'datetime': '2015-01-01T12:35:00Z', 'url': 'http://example.com/camel.txt'}], 'type': 'test-schema'}

    def package_create(context, data_dict):
[....]
            model.Session.rollback()
>           raise ValidationError(errors)
E           ValidationError: None - {'resources': [{u'datetime': [u'Date format incorrect']}]}

ckan/logic/action/create.py:182: ValidationError
==================== 1 failed, 148 passed in 64.71 seconds =====================
Command not successful. Returned 1
Tests not successful. Returned: 1