Add support for recurrences using the 'rec' tag.

(C) A weekly recurring todo due:1w rec:1w

Recurrence.py

+""" This module deals with recurring tasks. """
+
+from datetime import date, timedelta
+
+import Config
+from RelativeDate import relative_date_to_date
+import Todo
+
+class NoRecurrenceException(Exception):
+  pass
+
+def _get_due_date(p_todo):
+    """
+    Gets the due date of a todo as a date object. Defaults to today when the
+    todo has no due date, or when the due date was in the past.
+    """
+
+    due = p_todo.due_date()
+
+    if not due or due < date.today():
+        due = date.today()
+
+    return due
+
+def advance_recurring_todo(p_todo):
+    """
+    Given a Todo item, return a new instance of a Todo item with the dates
+    shifted according to the recurrence rule.
+
+    When no recurrence tag is present, an exception is raised.
+    """
+
+    todo = Todo.Todo(p_todo.source())
+    pattern = todo.tag_value('rec')
+
+    if not pattern:
+        raise NoRecurrenceException()
+
+    due = _get_due_date(todo)
+    length = todo.length()
+
+    new_due = relative_date_to_date(pattern, due)
+    todo.set_tag(Config.TAG_DUE, new_due.isoformat())
+
+    if todo.start_date():
+        new_start = new_due - timedelta(length)
+        todo.set_tag(Config.TAG_START, new_start.isoformat())
+
+    return todo

test/RecurrenceTest.py

+from datetime import date, timedelta
+import unittest
+
+import Config
+from Recurrence import advance_recurring_todo, NoRecurrenceException
+import Todo
+
+class RelativeDateTester(unittest.TestCase):
+    def setUp(self):
+        self.todo = Todo.Todo("Test rec:1w")
+
+    def test_duedate1(self):
+        """ Where due date is in the future. """
+        future = date.today() + timedelta(1)
+        new_due = date.today() + timedelta(8)
+
+        self.todo.set_tag(Config.TAG_DUE, future.isoformat())
+        new_todo = advance_recurring_todo(self.todo)
+
+        self.assertEquals(new_todo.due_date(), new_due)
+
+    def test_duedate2(self):
+        """ Where due date is today. """
+        todo = date.today()
+        new_due = date.today() + timedelta(7)
+
+        self.todo.set_tag(Config.TAG_DUE, todo.isoformat())
+        new_todo = advance_recurring_todo(self.todo)
+
+        self.assertEquals(new_todo.due_date(), new_due)
+
+    def test_duedate3(self):
+        """ Where due date is in the past. """
+        past = date.today() - timedelta(8)
+        new_due = date.today() + timedelta(7)
+
+        self.todo.set_tag(Config.TAG_DUE, past.isoformat())
+        new_todo = advance_recurring_todo(self.todo)
+
+        self.assertEquals(new_todo.due_date(), new_due)
+
+    def test_noduedate(self):
+        new_due = date.today() + timedelta(7)
+        new_todo = advance_recurring_todo(self.todo)
+
+        self.assertTrue(new_todo.has_tag(Config.TAG_DUE))
+        self.assertEquals(new_todo.due_date(), new_due)
+
+    def test_startdate(self):
+        """ Start date is before due date. """
+        self.todo.set_tag(Config.TAG_DUE, date.today().isoformat())
+        yesterday = date.today() - timedelta(1)
+        self.todo.set_tag(Config.TAG_START, yesterday.isoformat())
+
+        new_start = date.today() + timedelta(6)
+        new_todo = advance_recurring_todo(self.todo)
+
+        self.assertEquals(new_todo.start_date(), new_start)
+
+    def test_startdate2(self):
+        """ Start date equals due date. """
+        self.todo.set_tag(Config.TAG_DUE, date.today().isoformat())
+        self.todo.set_tag(Config.TAG_START, date.today().isoformat())
+
+        new_start = date.today() + timedelta(7)
+        new_todo = advance_recurring_todo(self.todo)
+
+        self.assertEquals(new_todo.start_date(), new_start)
+
+    def test_no_recurrence(self):
+        self.todo.remove_tag('rec')
+        self.assertRaises(NoRecurrenceException,advance_recurring_todo,self.todo)