--- /dev/null
+[report]
+omit = */tests.py
 
   - TASK_VERSION=v2.2.0
   - TASK_VERSION=v2.3.0
   - TASK_VERSION=v2.4.0
-  - TASK_VERSION=2.4.1
+  - TASK_VERSION=v2.4.1
+  - TASK_VERSION=2.4.2
 python:
   - "2.6"
   - "2.7"
 
 # built documents.
 #
 # The short X.Y version.
-version = '0.8.0'
+version = '0.9.0'
 # The full version, including alpha/beta/rc tags.
-release = '0.8.0'
+release = '0.9.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
 
     >>> task['id']
     15
     >>> task['due']
-    datetime.datetime(2013, 12, 5, 0, 0)
+    datetime.datetime(2015, 2, 5, 0, 0, tzinfo=<DstTzInfo 'Europe/Berlin' CET+1:00:00 STD>)
     >>> task['tags']
     ['work', 'servers']
 
     >>> task3 == task1
     True
 
+Accessing original values
+-------------------------
+
+To access the saved state of the Task, use dict-like access using the
+``original`` attribute:
+
+    >>> t = Task(tw, description="tidy up")
+    >>> t.save()
+    >>> t['description'] = "tidy up the kitchen and bathroom"
+    >>> t['description']
+    "tidy up the kitchen and bathroom"
+    >>> t.original['description']
+    "tidy up"
+
+When you save the task, original values are refreshed to reflect the
+saved state of the task:
+
+    >>> t.save()
+    >>> t.original['description']
+    "tidy up the kitchen and bathroom"
+
+Dealing with dates and time
+---------------------------
+
+Any timestamp-like attributes of the tasks are converted to timezone-aware
+datetime objects. To achieve this, Tasklib leverages ``pytz`` Python module,
+which brings the Olsen timezone databaze to Python.
+
+This shields you from annoying details of Daylight Saving Time shifts
+or conversion between different timezones. For example, to list all the
+tasks which are due midnight if you're currently in Berlin:
+
+    >>> myzone = pytz.timezone('Europe/Berlin')
+    >>> midnight = myzone.localize(datetime(2015,2,2,0,0,0))
+    >>> tw.tasks.filter(due__before=midnight)
+
+However, this is still a little bit tedious. That's why TaskWarrior object
+is capable of automatic timezone detection, using the ``tzlocal`` Python
+module. If your system timezone is set to 'Europe/Berlin', following example
+will work the same way as the previous one:
+
+    >>> tw.tasks.filter(due__before=datetime(2015,2,2,0,0,0))
+
+You can also use simple dates when filtering:
+
+    >>> tw.tasks.filter(due__before=date(2015,2,2))
+
+In such case, a 00:00:00 is used as the time component.
+
+Of course, you can use datetime naive objects when initializing Task object
+or assigning values to datetime atrributes:
+
+    >>> t = Task(tw, description="Buy new shoes", due=date(2015,2,5))
+    >>> t['due']
+    datetime.datetime(2015, 2, 5, 0, 0, tzinfo=<DstTzInfo 'Europe/Berlin' CET+1:00:00 STD>)
+    >>> t['due'] = date(2015,2,6,15,15,15)
+    >>> t['due']
+    datetime.datetime(2015, 2, 6, 15, 15, 15, tzinfo=<DstTzInfo 'Europe/Berlin' CET+1:00:00 STD>)
+
+However, since timezone-aware and timezone-naive datetimes are not comparable
+in Python, this can cause some unexpected behaviour:
+
+    >>> from datetime import datetime
+    >>> now = datetime.now()
+    >>> t = Task(tw, description="take out the trash now") 
+    >>> t['due'] = now
+    >>> now
+    datetime.datetime(2015, 2, 1, 19, 44, 4, 770001)
+    >>> t['due']
+    datetime.datetime(2015, 2, 1, 19, 44, 4, 770001, tzinfo=<DstTzInfo 'Europe/Berlin' CET+1:00:00 STD>)
+    >>> t['due'] == now
+    Traceback (most recent call last):
+      File "<stdin>", line 1, in <module>
+      TypeError: can't compare offset-naive and offset-aware datetimes
+
+If you want to compare datetime aware value with datetime naive value, you need
+to localize the naive value first:
+
+    >>> from datetime import datetime
+    >>> from tasklib.task import local_zone
+    >>> now = local_zone.localize(datetime.now())
+    >>> t['due'] = now
+    >>> now
+    datetime.datetime(2015, 2, 1, 19, 44, 4, 770001, tzinfo=<DstTzInfo 'Europe/Berlin' CET+1:00:00 STD>)
+    >>> t['due'] == now
+    True
+
+Also, note that it does not matter whether the timezone aware datetime objects
+are set in the same timezone:
+
+    >>> import pytz
+    >>> t['due']
+    datetime.datetime(2015, 2, 1, 19, 44, 4, 770001, tzinfo=<DstTzInfo 'Europe/Berlin' CET+1:00:00 STD>)
+    >>> now.astimezone(pytz.utc)
+    datetime.datetime(2015, 2, 1, 18, 44, 4, 770001, tzinfo=<UTC>)
+    >>> t['due'] == now.astimezone(pytz.utc)
+    True
+
+
 Working with annotations
 ------------------------
 
 
     >>> annotation = annotated_task['annotations'][0]
     >>> annotation['entry']
-    datetime.datetime(2015, 1, 3, 21, 13, 55)
+    datetime.datetime(2015, 1, 3, 21, 13, 55, tzinfo=<DstTzInfo 'Europe/Berlin' CET+1:00:00 STD>)
     >>> annotation['description']
     u'Yeah, I am annotated!'
 
 This removes the need for maintaining two copies of the same code base and/or
 boilerplate code.
 
+In ``on-modify`` events, tasklib loads both the original version and the modified
+version of the task to the returned ``Task`` object. To access the original data
+(in read-only manner), use ``original`` dict-like attribute:
+
+    >>> t = Task.from_input()
+    >>> t['description']
+    "Modified description"
+    >>> t.original['description']
+    "Original description"
 
 Working with UDAs
 -----------------
 
 from setuptools import setup, find_packages
 
-version = '0.8.0'
+version = '0.9.0'
 
 setup(
     name='tasklib',
     packages=find_packages(),
     include_package_data=True,
     test_suite='tasklib.tests',
-    install_requires=['six==1.5.2'],
+    install_requires=['six==1.5.2', 'pytz', 'tzlocal'],
     classifiers=[
         'Development Status :: 4 - Beta',
         'Programming Language :: Python',
 
 import json
 import logging
 import os
+import pytz
 import six
 import sys
 import subprocess
+import tzlocal
 
 DATE_FORMAT = '%Y%m%dT%H%M%SZ'
 REPR_OUTPUT_SIZE = 10
 VERSION_2_4_0 = six.u('2.4.0')
 
 logger = logging.getLogger(__name__)
+local_zone = tzlocal.get_localzone()
 
 
 class TaskWarriorException(Exception):
     pass
 
 
+class ReadOnlyDictView(object):
+    """
+    Provides simplified read-only view upon dict object.
+    """
+
+    def __init__(self, viewed_dict):
+        self.viewed_dict = viewed_dict
+
+    def __getitem__(self, key):
+        return copy.deepcopy(self.viewed_dict.__getitem__(key))
+
+    def __contains__(self, k):
+        return self.viewed_dict.__contains__(k)
+
+    def __iter__(self):
+        for value in self.viewed_dict:
+            yield copy.deepcopy(value)
+
+    def __len__(self):
+        return len(self.viewed_dict)
+
+    def get(self, key, default=None):
+        return copy.deepcopy(self.viewed_dict.get(key, default))
+
+    def items(self):
+        return [copy.deepcopy(v) for v in self.viewed_dict.items()]
+
+    def values(self):
+        return [copy.deepcopy(v) for v in self.viewed_dict.values()]
+
+
 class SerializingObject(object):
     """
     Common ancestor for TaskResource & TaskFilter, since they both
         not export empty-valued attributes) if the attribute
         is not iterable (e.g. list or set), in which case
         a empty iterable should be used.
+
+    Normalizing methods should hold the following contract:
+      - They are used to validate and normalize the user input.
+        Any attribute value that comes from the user (during Task
+        initialization, assignign values to Task attributes, or
+        filtering by user-provided values of attributes) is first
+        validated and normalized using the normalize_{key} method.
+      - If validation or normalization fails, normalizer is expected
+        to raise ValueError.
     """
 
     def _deserialize(self, key, value):
                                  lambda x: x if x is not None else '')
         return dehydrate_func(value)
 
+    def _normalize(self, key, value):
+        """
+        Use normalize_<key> methods to normalize user input. Any user
+        input will be normalized at the moment it is used as filter,
+        or entered as a value of Task attribute.
+        """
+
+        # None value should not be converted by normalizer
+        if value is None:
+            return None
+
+        normalize_func = getattr(self, 'normalize_{0}'.format(key),
+                                 lambda x: x)
+
+        return normalize_func(value)
+
     def timestamp_serializer(self, date):
         if not date:
             return ''
+
+        # Any serialized timestamp should be localized, we need to
+        # convert to UTC before converting to string (DATE_FORMAT uses UTC)
+        date = date.astimezone(pytz.utc)
+
         return date.strftime(DATE_FORMAT)
 
     def timestamp_deserializer(self, date_str):
         if not date_str:
             return None
-        return datetime.datetime.strptime(date_str, DATE_FORMAT)
+
+        # Return timestamp localized in the local zone
+        naive_timestamp = datetime.datetime.strptime(date_str, DATE_FORMAT)
+        localized_timestamp = pytz.utc.localize(naive_timestamp)
+        return localized_timestamp.astimezone(local_zone)
 
     def serialize_entry(self, value):
         return self.timestamp_serializer(value)
     def deserialize_entry(self, value):
         return self.timestamp_deserializer(value)
 
+    def normalize_entry(self, value):
+        return self.datetime_normalizer(value)
+
     def serialize_modified(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_modified(self, value):
         return self.timestamp_deserializer(value)
 
+    def normalize_modified(self, value):
+        return self.datetime_normalizer(value)
+
+    def serialize_start(self, value):
+        return self.timestamp_serializer(value)
+
+    def deserialize_start(self, value):
+        return self.timestamp_deserializer(value)
+
+    def normalize_start(self, value):
+        return self.datetime_normalizer(value)
+
+    def serialize_end(self, value):
+        return self.timestamp_serializer(value)
+
+    def deserialize_end(self, value):
+        return self.timestamp_deserializer(value)
+
+    def normalize_end(self, value):
+        return self.datetime_normalizer(value)
+
     def serialize_due(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_due(self, value):
         return self.timestamp_deserializer(value)
 
+    def normalize_due(self, value):
+        return self.datetime_normalizer(value)
+
     def serialize_scheduled(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_scheduled(self, value):
         return self.timestamp_deserializer(value)
 
+    def normalize_scheduled(self, value):
+        return self.datetime_normalizer(value)
+
     def serialize_until(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_until(self, value):
         return self.timestamp_deserializer(value)
 
+    def normalize_until(self, value):
+        return self.datetime_normalizer(value)
+
     def serialize_wait(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_wait(self, value):
         return self.timestamp_deserializer(value)
 
+    def normalize_wait(self, value):
+        return self.datetime_normalizer(value)
+
+    def serialize_annotations(self, value):
+        value = value if value is not None else []
+
+        # This may seem weird, but it's correct, we want to export
+        # a list of dicts as serialized value
+        serialized_annotations = [json.loads(annotation.export_data())
+                                  for annotation in value]
+        return serialized_annotations if serialized_annotations else ''
+
     def deserialize_annotations(self, data):
         return [TaskAnnotation(self, d) for d in data] if data else []
 
         uuids = raw_uuids.split(',')
         return set(self.warrior.tasks.get(uuid=uuid) for uuid in uuids if uuid)
 
+    def datetime_normalizer(self, value):
+        """
+        Normalizes date/datetime value (considered to come from user input)
+        to localized datetime value. Following conversions happen:
+
+        naive date -> localized datetime with the same date, and time=midnight
+        naive datetime -> localized datetime with the same value
+        localized datetime -> localized datetime (no conversion)
+        """
+
+        if (isinstance(value, datetime.date)
+            and not isinstance(value, datetime.datetime)):
+            # Convert to local midnight
+            value_full = datetime.datetime.combine(value, datetime.time.min)
+            localized = local_zone.localize(value_full)
+        elif isinstance(value, datetime.datetime) and value.tzinfo is None:
+            # Convert to localized datetime object
+            localized = local_zone.localize(value)
+        else:
+            # If the value is already localized, there is no need to change
+            # time zone at this point. Also None is a valid value too.
+            localized = value
+
+        return localized
+
+    def normalize_uuid(self, value):
+        # Enforce sane UUID
+        if not isinstance(value, six.string_types) or value == '':
+            raise ValueError("UUID must be a valid non-empty string, "
+                             "not: {}".format(value))
+
+        return value
+
 
 class TaskResource(SerializingObject):
     read_only_fields = []
     def __setitem__(self, key, value):
         if key in self.read_only_fields:
             raise RuntimeError('Field \'%s\' is read-only' % key)
+
+        # Normalize the user input before saving it
+        value = self._normalize(key, value)
         self._data[key] = value
 
     def __str__(self):
     def __repr__(self):
         return str(self)
 
+    def export_data(self):
+        """
+        Exports current data contained in the Task as JSON
+        """
+
+        # We need to remove spaces for TW-1504, use custom separators
+        data_tuples = ((key, self._serialize(key, value))
+                       for key, value in six.iteritems(self._data))
+
+        # Empty string denotes empty serialized value, we do not want
+        # to pass that to TaskWarrior.
+        data_tuples = filter(lambda t: t[1] is not '', data_tuples)
+        data = dict(data_tuples)
+        return json.dumps(data, separators=(',',':'))
+
+    @property
+    def _modified_fields(self):
+        writable_fields = set(self._data.keys()) - set(self.read_only_fields)
+        for key in writable_fields:
+            new_value = self._data.get(key)
+            old_value = self._original_data.get(key)
+
+            # Make sure not to mark data removal as modified field if the
+            # field originally had some empty value
+            if key in self._data and not new_value and not old_value:
+                continue
+
+            if new_value != old_value:
+                yield key
+
+    @property
+    def modified(self):
+        return bool(list(self._modified_fields))
+
 
 class TaskAnnotation(TaskResource):
     read_only_fields = ['entry', 'description']
         pass
 
     @classmethod
-    def from_input(cls, input_file=sys.stdin, modify=None):
+    def from_input(cls, input_file=sys.stdin, modify=None, warrior=None):
         """
         Creates a Task object, directly from the stdin, by reading one line.
         If modify=True, two lines are used, first line interpreted as the
         but defaults to sys.stdin.
         """
 
-        # TaskWarrior instance is set to None
-        task = cls(None)
-
         # Detect the hook type if not given directly
         name = os.path.basename(sys.argv[0])
         modify = name.startswith('on-modify') if modify is None else modify
 
+        # Create the TaskWarrior instance if none passed
+        if warrior is None:
+            hook_parent_dir = os.path.dirname(os.path.dirname(sys.argv[0]))
+            warrior = TaskWarrior(data_location=hook_parent_dir)
+
+        # TaskWarrior instance is set to None
+        task = cls(warrior)
+
         # Load the data from the input
         task._load_data(json.loads(input_file.readline().strip()))
 
         # __init__ methods, that would be confusing
 
         # Rather unfortunate syntax due to python2.6 comaptiblity
-        self._load_data(dict((key, self._serialize(key, value))
-                        for (key, value) in six.iteritems(kwargs)))
+        self._data = dict((key, self._normalize(key, value))
+                          for (key, value) in six.iteritems(kwargs))
+        self._original_data = copy.deepcopy(self._data)
+
+        # Provide read only access to the original data
+        self.original = ReadOnlyDictView(self._original_data)
 
     def __unicode__(self):
         return self['description']
             # If the tasks are not saved, return hash of instance id
             return id(self).__hash__()
 
-    @property
-    def _modified_fields(self):
-        writable_fields = set(self._data.keys()) - set(self.read_only_fields)
-        for key in writable_fields:
-            new_value = self._data.get(key)
-            old_value = self._original_data.get(key)
-
-            # Make sure not to mark data removal as modified field if the
-            # field originally had some empty value
-            if key in self._data and not new_value and not old_value:
-                continue
-
-            if new_value != old_value:
-                yield key
-
-    @property
-    def modified(self):
-        return bool(list(self._modified_fields))
-
     @property
     def completed(self):
         return self['status'] == six.text_type('completed')
         self.warrior.execute_command([self['uuid'], 'delete'])
 
         # Refresh the status again, so that we have updated info stored
+        self.refresh(only_fields=['status', 'start', 'end'])
+
+    def start(self):
+        if not self.saved:
+            raise Task.NotSaved("Task needs to be saved before it can be started")
+
+        # Refresh, and raise exception if task is already completed/deleted
         self.refresh(only_fields=['status'])
 
+        if self.completed:
+            raise Task.CompletedTask("Cannot start a completed task")
+        elif self.deleted:
+            raise Task.DeletedTask("Deleted task cannot be started")
+
+        self.warrior.execute_command([self['uuid'], 'start'])
+
+        # Refresh the status again, so that we have updated info stored
+        self.refresh(only_fields=['status', 'start'])
 
     def done(self):
         if not self.saved:
         self.warrior.execute_command([self['uuid'], 'done'])
 
         # Refresh the status again, so that we have updated info stored
-        self.refresh(only_fields=['status'])
+        self.refresh(only_fields=['status', 'start', 'end'])
 
     def save(self):
         if self.saved and not self.modified:
         else:
             self._load_data(new_data)
 
-    def export_data(self):
-        """
-        Exports current data contained in the Task as JSON
-        """
-
-        # We need to remove spaces for TW-1504, use custom separators
-        data_tuples = ((key, self._serialize(key, value))
-                       for key, value in six.iteritems(self._data))
-
-        # Empty string denotes empty serialized value, we do not want
-        # to pass that to TaskWarrior.
-        data_tuples = filter(lambda t: t[1] is not '', data_tuples)
-        data = dict(data_tuples)
-        return json.dumps(data, separators=(',',':'))
-
 class TaskFilter(SerializingObject):
     """
     A set of parameters to filter the task list with.
         # Replace the value with empty string, since that is the
         # convention in TW for empty values
         attribute_key = key.split('.')[0]
+
+        # Since this is user input, we need to normalize before we serialize
+        value = self._normalize(key, value)
         value = self._serialize(attribute_key, value)
 
         # If we are filtering by uuid:, do not use uuid keyword
         self.config = {
             'data.location': os.path.expanduser(data_location),
             'confirmation': 'no',
-            'dependency.confirmation': 'no', # See TW-1483 or taskrc man page
+            'dependency.confirmation': 'no',  # See TW-1483 or taskrc man page
+            'recurrence.confirmation': 'no',  # Necessary for modifying R tasks
         }
         self.tasks = TaskQuerySet(self)
         self.version = self._get_version()
         stdout, stderr = [x.decode('utf-8') for x in p.communicate()]
         return stdout.strip('\n')
 
-    def execute_command(self, args, config_override={}):
+    def execute_command(self, args, config_override={}, allow_failure=True):
         command_args = self._get_command_args(
             args, config_override=config_override)
         logger.debug(' '.join(command_args))
         p = subprocess.Popen(command_args, stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE)
         stdout, stderr = [x.decode('utf-8') for x in p.communicate()]
-        if p.returncode:
+        if p.returncode and allow_failure:
             if stderr.strip():
-                error_msg = stderr.strip().splitlines()[-1]
+                error_msg = stderr.strip()
             else:
                 error_msg = stdout.strip()
             raise TaskWarriorException(error_msg)
         return stdout.strip().split('\n')
 
+    def enforce_recurrence(self):
+        # Run arbitrary report command which will trigger generation
+        # of recurrent tasks.
+        # TODO: Make a version dependant enforcement once
+        #       TW-1531 is handled
+        self.execute_command(['next'], allow_failure=False)
+
     def filter_tasks(self, filter_obj):
+        self.enforce_recurrence()
         args = ['export', '--'] + filter_obj.get_filter_params()
         tasks = []
         for line in self.execute_command(args):
 
 # coding=utf-8
 
+import copy
 import datetime
 import itertools
+import json
+import pytz
 import six
 import shutil
 import tempfile
 import unittest
 
-from .task import TaskWarrior, Task
+from .task import TaskWarrior, Task, ReadOnlyDictView, local_zone, DATE_FORMAT
 
 # http://taskwarrior.org/docs/design/task.html , Section: The Attributes
 TASK_STANDARD_ATTRS = (
     'priority',
     'depends',
     'tags',
-    'annotation',
+    'annotations',
 )
 
 class TasklibTest(unittest.TestCase):
         filtered_task = self.tw.tasks.get(project="random")
         self.assertEqual(filtered_task['project'], "random")
 
+    def test_filter_with_empty_uuid(self):
+        self.assertRaises(ValueError, lambda: self.tw.tasks.get(uuid=''))
+
+    def test_filter_dummy_by_status(self):
+        t = Task(self.tw, description="test")
+        t.save()
+
+        tasks = self.tw.tasks.filter(status=t['status'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_uuid(self):
+        t = Task(self.tw, description="test")
+        t.save()
+
+        tasks = self.tw.tasks.filter(uuid=t['uuid'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_entry(self):
+        t = Task(self.tw, description="test")
+        t.save()
+
+        tasks = self.tw.tasks.filter(entry=t['entry'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_description(self):
+        t = Task(self.tw, description="test")
+        t.save()
+
+        tasks = self.tw.tasks.filter(description=t['description'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_start(self):
+        t = Task(self.tw, description="test")
+        t.save()
+        t.start()
+
+        tasks = self.tw.tasks.filter(start=t['start'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_end(self):
+        t = Task(self.tw, description="test")
+        t.save()
+        t.done()
+
+        tasks = self.tw.tasks.filter(end=t['end'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_due(self):
+        t = Task(self.tw, description="test", due=datetime.datetime.now())
+        t.save()
+
+        tasks = self.tw.tasks.filter(due=t['due'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_until(self):
+        t = Task(self.tw, description="test")
+        t.save()
+
+        tasks = self.tw.tasks.filter(until=t['until'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_modified(self):
+        # Older TW version does not support bumping modified
+        # on save
+        if self.tw.version < six.text_type('2.2.0'):
+            # Python2.6 does not support SkipTest. As a workaround
+            # mark the test as passed by exiting.
+            if getattr(unittest, 'SkipTest', None) is not None:
+                raise unittest.SkipTest()
+            else:
+                return
+
+        t = Task(self.tw, description="test")
+        t.save()
+
+        tasks = self.tw.tasks.filter(modified=t['modified'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_scheduled(self):
+        t = Task(self.tw, description="test")
+        t.save()
+
+        tasks = self.tw.tasks.filter(scheduled=t['scheduled'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_tags(self):
+        t = Task(self.tw, description="test", tags=["home"])
+        t.save()
+
+        tasks = self.tw.tasks.filter(tags=t['tags'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_dummy_by_projects(self):
+        t = Task(self.tw, description="test", project="random")
+        t.save()
+
+        tasks = self.tw.tasks.filter(project=t['project'])
+        self.assertEqual(list(tasks), [t])
+
+    def test_filter_by_priority(self):
+        t = Task(self.tw, description="test", priority="H")
+        t.save()
+
+        tasks = self.tw.tasks.filter(priority=t['priority'])
+        self.assertEqual(list(tasks), [t])
+
 
 class TaskTest(TasklibTest):
 
         t = Task(self.tw, description="test task")
         self.assertRaises(Task.NotSaved, t.refresh)
 
+    def test_start_unsaved_task(self):
+        t = Task(self.tw, description="test task")
+        self.assertRaises(Task.NotSaved, t.start)
+
     def test_delete_deleted_task(self):
         t = Task(self.tw, description="test task")
         t.save()
 
         self.assertRaises(Task.CompletedTask, t.done)
 
+    def test_start_completed_task(self):
+        t = Task(self.tw, description="test task")
+        t.save()
+        t.done()
+
+        self.assertRaises(Task.CompletedTask, t.start)
+
     def test_complete_deleted_task(self):
         t = Task(self.tw, description="test task")
         t.save()
 
         self.assertRaises(Task.DeletedTask, t.done)
 
+    def test_start_completed_task(self):
+        t = Task(self.tw, description="test task")
+        t.save()
+        t.done()
+
+        self.assertRaises(Task.CompletedTask, t.start)
+
+    def test_starting_task(self):
+        t = Task(self.tw, description="test task")
+        now = t.datetime_normalizer(datetime.datetime.now())
+        t.save()
+        t.start()
+
+        self.assertTrue(now.replace(microsecond=0) <= t['start'])
+        self.assertEqual(t['status'], 'pending')
+
+    def test_completing_task(self):
+        t = Task(self.tw, description="test task")
+        now = t.datetime_normalizer(datetime.datetime.now())
+        t.save()
+        t.done()
+
+        self.assertTrue(now.replace(microsecond=0) <= t['end'])
+        self.assertEqual(t['status'], 'completed')
+
+    def test_deleting_task(self):
+        t = Task(self.tw, description="test task")
+        now = t.datetime_normalizer(datetime.datetime.now())
+        t.save()
+        t.delete()
+
+        self.assertTrue(now.replace(microsecond=0) <= t['end'])
+        self.assertEqual(t['status'], 'deleted')
+
     def test_modify_simple_attribute_without_space(self):
         t = Task(self.tw, description="test")
         t.save()
         for deserializer in deserializers:
             self.assertTrue(deserializer('') in (None, [], set()))
 
+    def test_normalizers_handling_none(self):
+        # Test that any normalizer can handle None as a valid value
+        t = Task(self.tw)
+
+        for key in TASK_STANDARD_ATTRS:
+            t._normalize(key, None)
 
+    def test_recurrent_task_generation(self):
+        today = datetime.date.today()
+        t = Task(self.tw, description="brush teeth",
+                 due=today, recur="daily")
+        t.save()
+        self.assertEqual(len(self.tw.tasks.pending()), 2)
 
 class TaskFromHookTest(TasklibTest):
 
          '"description":"test task"}')
 
     def test_setting_up_from_add_hook_input(self):
-        t = Task.from_input(input_file=self.input_add_data)
+        t = Task.from_input(input_file=self.input_add_data, warrior=self.tw)
         self.assertEqual(t['description'], "Buy some milk")
         self.assertEqual(t.pending, True)
 
     def test_setting_up_from_modified_hook_input(self):
-        t = Task.from_input(input_file=self.input_modify_data, modify=True)
+        t = Task.from_input(input_file=self.input_modify_data, modify=True,
+                            warrior=self.tw)
         self.assertEqual(t['description'], "Buy some milk finally")
         self.assertEqual(t.pending, False)
         self.assertEqual(t.completed, True)
 
     def test_export_data(self):
         t = Task(self.tw, description="test task",
-            project="Home", due=datetime.datetime(2015,1,1,23,23,23))
+            project="Home",
+            due=pytz.utc.localize(datetime.datetime(2015,1,1,23,23,23)))
 
         # Check that the output is a permutation of:
         # {"project":"Home","description":"test task","due":"20150101232323Z"}
         self.assertTrue(any(t.export_data() == expected
                             for expected in allowed_output))
 
+class TimezoneAwareDatetimeTest(TasklibTest):
+
+    def setUp(self):
+        super(TimezoneAwareDatetimeTest, self).setUp()
+        self.zone = local_zone
+        self.localdate_naive = datetime.datetime(2015,2,2)
+        self.localtime_naive = datetime.datetime(2015,2,2,0,0,0)
+        self.localtime_aware = self.zone.localize(self.localtime_naive)
+        self.utctime_aware = self.localtime_aware.astimezone(pytz.utc)
+
+    def test_timezone_naive_datetime_setitem(self):
+        t = Task(self.tw, description="test task")
+        t['due'] = self.localtime_naive
+        self.assertEqual(t['due'], self.localtime_aware)
+
+    def test_timezone_naive_datetime_using_init(self):
+        t = Task(self.tw, description="test task", due=self.localtime_naive)
+        self.assertEqual(t['due'], self.localtime_aware)
+
+    def test_filter_by_naive_datetime(self):
+        t = Task(self.tw, description="task1", due=self.localtime_naive)
+        t.save()
+        matching_tasks = self.tw.tasks.filter(due=self.localtime_naive)
+        self.assertEqual(len(matching_tasks), 1)
+
+    def test_serialize_naive_datetime(self):
+        t = Task(self.tw, description="task1", due=self.localtime_naive)
+        self.assertEqual(json.loads(t.export_data())['due'], 
+                         self.utctime_aware.strftime(DATE_FORMAT))
+
+    def test_timezone_naive_date_setitem(self):
+        t = Task(self.tw, description="test task")
+        t['due'] = self.localdate_naive
+        self.assertEqual(t['due'], self.localtime_aware)
+
+    def test_timezone_naive_date_using_init(self):
+        t = Task(self.tw, description="test task", due=self.localdate_naive)
+        self.assertEqual(t['due'], self.localtime_aware)
+
+    def test_filter_by_naive_date(self):
+        t = Task(self.tw, description="task1", due=self.localdate_naive)
+        t.save()
+        matching_tasks = self.tw.tasks.filter(due=self.localdate_naive)
+        self.assertEqual(len(matching_tasks), 1)
+
+    def test_serialize_naive_date(self):
+        t = Task(self.tw, description="task1", due=self.localdate_naive)
+        self.assertEqual(json.loads(t.export_data())['due'], 
+                         self.utctime_aware.strftime(DATE_FORMAT))
+
+    def test_timezone_aware_datetime_setitem(self):
+        t = Task(self.tw, description="test task")
+        t['due'] = self.localtime_aware
+        self.assertEqual(t['due'], self.localtime_aware)
+
+    def test_timezone_aware_datetime_using_init(self):
+        t = Task(self.tw, description="test task", due=self.localtime_aware)
+        self.assertEqual(t['due'], self.localtime_aware)
+
+    def test_filter_by_aware_datetime(self):
+        t = Task(self.tw, description="task1", due=self.localtime_aware)
+        t.save()
+        matching_tasks = self.tw.tasks.filter(due=self.localtime_aware)
+        self.assertEqual(len(matching_tasks), 1)
+
+    def test_serialize_aware_datetime(self):
+        t = Task(self.tw, description="task1", due=self.localtime_aware)
+        self.assertEqual(json.loads(t.export_data())['due'], 
+                         self.utctime_aware.strftime(DATE_FORMAT))
 
 class AnnotationTest(TasklibTest):
 
          task.save()
          self.assertEqual(task['project'], 'test')
 
+    def test_serialize_annotations(self):
+        # Test that serializing annotations is possible
+        t = Task(self.tw, description="test")
+        t.save()
+
+        t.add_annotation("annotation1")
+        t.add_annotation("annotation2")
+
+        data = t._serialize('annotations', t._data['annotations'])
+
+        self.assertEqual(len(data), 2)
+        self.assertEqual(type(data[0]), dict)
+        self.assertEqual(type(data[1]), dict)
+
+        self.assertEqual(data[0]['description'], "annotation1")
+        self.assertEqual(data[1]['description'], "annotation2")
+
 
 class UnicodeTest(TasklibTest):
 
     def test_non_unicode_task(self):
         Task(self.tw, description="test task").save()
         self.tw.tasks.get()
+
+class ReadOnlyDictViewTest(unittest.TestCase):
+
+    def setUp(self):
+        self.sample = dict(l=[1,2,3], d={'k':'v'})
+        self.original_sample = copy.deepcopy(self.sample)
+        self.view = ReadOnlyDictView(self.sample)
+
+    def test_readonlydictview_getitem(self):
+        l = self.view['l']
+        self.assertEqual(l, self.sample['l'])
+
+        # Assert that modification changed only copied value
+        l.append(4)
+        self.assertNotEqual(l, self.sample['l'])
+
+        # Assert that viewed dict is not changed
+        self.assertEqual(self.sample, self.original_sample)
+
+    def test_readonlydictview_contains(self):
+        self.assertEqual('l' in self.view, 'l' in self.sample)
+        self.assertEqual('d' in self.view, 'd' in self.sample)
+        self.assertEqual('k' in self.view, 'k' in self.sample)
+
+        # Assert that viewed dict is not changed
+        self.assertEqual(self.sample, self.original_sample)
+
+    def test_readonlydictview_iter(self):
+        self.assertEqual(list(k for k in self.view),
+                         list(k for k in self.sample))
+
+        # Assert the view is correct after modification
+        self.sample['new'] = 'value'
+        self.assertEqual(list(k for k in self.view),
+                         list(k for k in self.sample))
+
+    def test_readonlydictview_len(self):
+        self.assertEqual(len(self.view), len(self.sample))
+
+        # Assert the view is correct after modification
+        self.sample['new'] = 'value'
+        self.assertEqual(len(self.view), len(self.sample))
+
+    def test_readonlydictview_get(self):
+        l = self.view.get('l')
+        self.assertEqual(l, self.sample.get('l'))
+
+        # Assert that modification changed only copied value
+        l.append(4)
+        self.assertNotEqual(l, self.sample.get('l'))
+
+        # Assert that viewed dict is not changed
+        self.assertEqual(self.sample, self.original_sample)
+
+    def test_readonlydict_items(self):
+        view_items = self.view.items()
+        sample_items = list(self.sample.items())
+        self.assertEqual(view_items, sample_items)
+
+        view_items.append('newkey')
+        self.assertNotEqual(view_items, sample_items)
+        self.assertEqual(self.sample, self.original_sample)
+
+    def test_readonlydict_values(self):
+        view_values = self.view.values()
+        sample_values = list(self.sample.values())
+        self.assertEqual(view_values, sample_values)
+
+        view_list_item = list(filter(lambda x: type(x) is list,
+                                     view_values))[0]
+        view_list_item.append(4)
+        self.assertNotEqual(view_values, sample_values)
+        self.assertEqual(self.sample, self.original_sample)