Make start/end date fields store datetime objects internally

apps/openassessment/xblock/openassessmentblock.py

 """An XBlock where students can read a question and compose their response"""
 
 import datetime as dt
+import json
 import pkg_resources
 
 import pytz
@@ -11,7 +12,7 @@ from django.template.loader import get_template
 from webob import Response
 
 from xblock.core import XBlock
-from xblock.fields import List, Scope, String, Boolean
+from xblock.fields import DateTime, List, Scope, String, Boolean
 from xblock.fragment import Fragment
 from openassessment.xblock.grade_mixin import GradeMixin
 
@@ -168,12 +169,12 @@ class OpenAssessmentBlock(
     WorkflowMixin):
     """Displays a question and gives an area where students can compose a response."""
 
-    start = String(
+    start = DateTime(
         default=None, scope=Scope.settings,
         help="ISO-8601 formatted string representing the start date of this assignment."
     )
 
-    due = String(
+    due = DateTime(
         default=None, scope=Scope.settings,
         help="ISO-8601 formatted string representing the due date of this assignment."
     )
@@ -379,13 +380,11 @@ class OpenAssessmentBlock(
         context_dict["xblock_trace"] = self.get_xblock_trace()
 
         if self.start:
-            start = dateutil.parser.parse(self.start)
-            context_dict["formatted_start_date"] = start.strftime("%A, %B %d, %Y")
-            context_dict["formatted_start_datetime"] = start.strftime("%A, %B %d, %Y %X")
+            context_dict["formatted_start_date"] = self.start.strftime("%A, %B %d, %Y")
+            context_dict["formatted_start_datetime"] = self.start.strftime("%A, %B %d, %Y %X")
         if self.due:
-            due = dateutil.parser.parse(self.due)
-            context_dict["formatted_due_date"] = due.strftime("%A, %B %d, %Y")
-            context_dict["formatted_due_datetime"] = due.strftime("%A, %B %d, %Y %X")
+            context_dict["formatted_due_date"] = self.due.strftime("%A, %B %d, %Y")
+            context_dict["formatted_due_datetime"] = self.due.strftime("%A, %B %d, %Y %X")
 
         template = get_template(path)
         context = Context(context_dict)
@@ -503,4 +502,4 @@ class OpenAssessmentBlock(
         """
         for assessment in self.rubric_assessments:
             if assessment["name"] == mixin_name:
-                return assessment
+                return assessment
\ No newline at end of file

apps/openassessment/xblock/resolve_dates.py

@@ -25,12 +25,12 @@ DISTANT_PAST = dt.datetime(dt.MINYEAR, 1, 1, tzinfo=pytz.utc)
 DISTANT_FUTURE = dt.datetime(dt.MAXYEAR, 1, 1, tzinfo=pytz.utc)
 
 
-def _parse_date(date_string):
+def _parse_date(value):
     """
     Parse an ISO formatted datestring into a datetime object with timezone set to UTC.
 
     Args:
-        date_string (str): The ISO formatted date string.
+        value (str or datetime): The ISO formatted date string or datetime object.
 
     Returns:
         datetime.datetime
@@ -38,10 +38,17 @@ def _parse_date(date_string):
     Raises:
         InvalidDateFormat: The date string could not be parsed.
     """
-    try:
-        return parse_date(date_string).replace(tzinfo=pytz.utc)
-    except ValueError:
-        raise InvalidDateFormat(_("Could not parse date '{date}'").format(date=date_string))
+    if isinstance(value, dt.datetime):
+        return value.replace(tzinfo=pytz.utc)
+
+    elif isinstance(value, basestring):
+        try:
+            return parse_date(value).replace(tzinfo=pytz.utc)
+        except ValueError:
+            raise InvalidDateFormat(_("Could not parse date '{date}'").format(date=value))
+
+    else:
+        raise InvalidDateFormat(_("'{date}' must be a date string or datetime").format(date=value))
 
 
 def resolve_dates(start, end, date_ranges):
@@ -90,10 +97,10 @@ def resolve_dates(start, end, date_ranges):
 
 
     Args:
-        start (str, ISO date format): When the problem opens.  A value of None indicates that the problem is always open.
-        end (str, ISO date format): When the problem closes.  A value of None indicates that the problem never closes.
+        start (str, ISO date format, or datetime): When the problem opens.  A value of None indicates that the problem is always open.
+        end (str, ISO date format, or datetime): When the problem closes.  A value of None indicates that the problem never closes.
         date_ranges (list of tuples): list of (start, end) ISO date string tuples indicating
-            the start/end timestamps of each submission/assessment.
+            the start/end timestamps (date string or datetime) of each submission/assessment.
 
     Returns:
         start (datetime): The resolved start date

apps/openassessment/xblock/test/test_openassessment.py

@@ -63,6 +63,17 @@ class TestOpenAssessment(XBlockHandlerTestCase):
         self.assertTrue(submission_response.body.find("openassessment__response"))
         self.assertTrue(submission_response.body.find("April"))
 
+    @scenario('data/basic_scenario.xml')
+    def test_formatted_dates(self, xblock):
+
+        # Set start/due dates
+        xblock.start = dt.datetime(2014, 4, 1, 1, 1, 1)
+        xblock.due = dt.datetime(2014, 5, 1)
+
+        resp = xblock.render_peer_assessment({})
+        self.assertTrue(resp.body.find('Tuesday, April 01, 2014'))
+        self.assertTrue(resp.body.find('Thursday, May 01, 2014'))
+
     @scenario('data/basic_scenario.xml', user_id='Bob')
     def test_default_fields(self, xblock):
 

apps/openassessment/xblock/test/test_studio.py

@@ -48,7 +48,7 @@ class StudioViewTest(XBlockHandlerTestCase):
 
         # Set the XBlock's release date to the future,
         # so we are not restricted in what we can edit
-        xblock.start = dt.datetime(3000, 1, 1).replace(tzinfo=pytz.utc).isoformat()
+        xblock.start = dt.datetime(3000, 1, 1).replace(tzinfo=pytz.utc)
 
         request = json.dumps({'xml': self.load_fixture_str('data/updated_block.xml')})
 

apps/openassessment/xblock/test/test_xml.py

@@ -2,8 +2,11 @@
 Tests for serializing to/from XML.
 """
 import copy
+import datetime as dt
 import mock
 import lxml.etree as etree
+import pytz
+import dateutil.parser
 from django.test import TestCase
 from ddt import ddt, data, file_data, unpack
 from openassessment.xblock.openassessmentblock import OpenAssessmentBlock, UI_MODELS
@@ -12,6 +15,22 @@ from openassessment.xblock.xml import (
 )
 
 
+def _parse_date(value):
+    """
+    Parse test-data date into a TZ-aware datetime.
+
+    Args:
+        value (string or None): The value to parse.
+
+    Returns:
+        TZ-aware datetime or None.
+    """
+    if value is None:
+        return value
+    else:
+        return dateutil.parser.parse(value).replace(tzinfo=pytz.utc)
+
+
 @ddt
 class TestSerializeContent(TestCase):
     """
@@ -56,12 +75,13 @@ class TestSerializeContent(TestCase):
         """
         self.oa_block = mock.MagicMock(OpenAssessmentBlock)
 
+
     @file_data('data/serialize.json')
     def test_serialize(self, data):
         self.oa_block.title = data['title']
         self.oa_block.prompt = data['prompt']
-        self.oa_block.start = data['start']
-        self.oa_block.due = data['due']
+        self.oa_block.start = _parse_date(data['start'])
+        self.oa_block.due = _parse_date(data['due'])
         self.oa_block.submission_due = data['submission_due']
         self.oa_block.rubric_criteria = data['criteria']
         self.oa_block.rubric_assessments = data['assessments']
@@ -278,8 +298,8 @@ class TestUpdateFromXml(TestCase):
         self.oa_block.rubric_criteria = dict()
         self.oa_block.rubric_assessments = list()
 
-        self.oa_block.start = "2000-01-01T00:00:00"
-        self.oa_block.due = "3000-01-01T00:00:00"
+        self.oa_block.start = dt.datetime(2000, 1, 1).replace(tzinfo=pytz.utc)
+        self.oa_block.due = dt.datetime(3000, 1, 1).replace(tzinfo=pytz.utc)
         self.oa_block.submission_due = "2000-01-01T00:00:00"
 
     @file_data('data/update_from_xml.json')
@@ -294,8 +314,8 @@ class TestUpdateFromXml(TestCase):
         # Check that the contents of the modified XBlock are correct
         self.assertEqual(self.oa_block.title, data['title'])
         self.assertEqual(self.oa_block.prompt, data['prompt'])
-        self.assertEqual(self.oa_block.start, data['start'])
-        self.assertEqual(self.oa_block.due, data['due'])
+        self.assertEqual(self.oa_block.start, _parse_date(data['start']))
+        self.assertEqual(self.oa_block.due, _parse_date(data['due']))
         self.assertEqual(self.oa_block.submission_due, data['submission_due'])
         self.assertEqual(self.oa_block.rubric_criteria, data['criteria'])
         self.assertEqual(self.oa_block.rubric_assessments, data['assessments'])
@@ -314,4 +334,4 @@ class TestUpdateFromXml(TestCase):
             update_from_xml_str(
                 self.oa_block, "".join(data['xml']),
                 validator=lambda *args: (False, '')
-            )
+            )
\ No newline at end of file

requirements/base.txt

 # edX Internal Requirements
-git+https://github.com/edx/XBlock.git@c4055bc1#egg=XBlock
+git+https://github.com/edx/XBlock.git@c7ef611727d89887a258c5d4774a6efbda36cb13#egg=XBlock
 git+https://github.com/ormsbee/xblock-sdk.git@4f62e508#egg=xblock-sdk
 
 # Third Party Requirements