Add method to mark a todo as completed.

TodoBase.py

@@ -2,6 +2,7 @@
 This module contains the class that represents a single todo item.
 """
 
+import datetime
 import re
 
 import TodoParser
@@ -135,6 +136,18 @@ class TodoBase(object):
         """ Returns True iff this todo has been completed. """
         return self.fields['completed']
 
+    def set_completed(self):
+        """
+        Marks the todo as complete.
+        Sets the completed flag and sets the completion date to today.
+        """
+        self.fields['completed'] = True
+        today = datetime.date.today()
+        self.fields['completionDate'] = today
+
+        self.src = re.sub(r'^(\([A-Z]\) )?', \
+            'x ' + today.isoformat() + ' ', self.src)
+
     def __print__(self):
         """ A printer for the todo item. """
         print self.src + "\n"

test/TodoBaseTest.py

 """ Tests for the TodoBase class. """
 
+import datetime
 import re
 import unittest
 
@@ -144,5 +145,37 @@ class TodoBaseTester(unittest.TestCase):
 
         self.assertFalse(todo.is_completed())
 
+    def test_set_complete1(self):
+        todo = TodoBase.TodoBase("(A) Foo")
+        todo.set_completed()
+
+        today = datetime.date.today().isoformat()
+
+        self.assertTrue(re.match('^x ' + today + ' Foo', todo.src))
+
+    def test_set_complete2(self):
+        todo = TodoBase.TodoBase("2014-06-12 Foo")
+        todo.set_completed()
+
+        today = datetime.date.today().isoformat()
+
+        self.assertTrue(re.match('^x ' + today + ' 2014-06-12 Foo', todo.src))
+
+    def test_set_complete3(self):
+        todo = TodoBase.TodoBase("Foo")
+        todo.set_completed()
+
+        today = datetime.date.today().isoformat()
+
+        self.assertTrue(re.match('^x ' + today + ' Foo', todo.src))
+
+    def test_set_complete4(self):
+        todo = TodoBase.TodoBase("(A) 2014-06-12 Foo")
+        todo.set_completed()
+
+        today = datetime.date.today().isoformat()
+
+        self.assertTrue(re.match('^x ' + today + ' 2014-06-12 Foo', todo.src))
+
 if __name__ == '__main__':
     unittest.main()