Add tests for the priority command.

PriorityCommand.py

-import Command
+from Command import *
 from PrettyPrinter import pretty_print
-from Utils import convert_todo_number, is_valid_priority
+from TodoList import InvalidTodoException
+from Utils import *
 
-class PriorityCommand(Command.Command):
+class PriorityCommand(Command):
     def __init__(self, p_args, p_todolist,
                  p_out=lambda a: None,
                  p_err=lambda a: None,
                  p_prompt=lambda a: None):
         super(PriorityCommand, self).__init__(p_args, p_todolist, p_out, p_err, p_prompt)
-        self.number = convert_todo_number(self.argument(0))
-        self.todo = self.todolist.todo(self.number)
-        self.priority = self.argument(1)
 
     def execute(self):
-        if is_valid_priority(self.priority):
-            old_priority = self.todo.priority()
-            self.todolist.set_priority(self.number, self.priority)
+        number = None
+        priority = None
+        try:
+            number = convert_todo_number(self.argument(0))
+            priority = self.argument(1)
+            todo = self.todolist.todo(number)
 
-            self.out("Priority changed from %s to %s" % (old_priority, self.priority))
-            self.out(pretty_print(self.todo))
+            if is_valid_priority(priority):
+                old_priority = todo.priority()
+                self.todolist.set_priority(todo, priority)
+
+                if old_priority and priority:
+                    self.out("Priority changed from %s to %s" % (old_priority, priority))
+                else:
+                    self.out("Priority set to %s." % priority)
+
+                self.out(pretty_print(todo))
             else:
                 self.error("Invalid priority given.")
+        except InvalidCommandArgument:
+            self.error(self.usage())
+        except (InvalidTodoNumberException, InvalidTodoException):
+            if number and priority:
+                self.error( "Invalid todo number given.")
+            else:
+                self.error(self.usage())

Utils.py

@@ -39,4 +39,4 @@ def convert_todo_number(p_number):
     return p_number
 
 def is_valid_priority(p_priority):
-    return re.match(r'^[A-Z]$', p_priority) != None
+    return p_priority != None and re.match(r'^[A-Z]$', p_priority) != None

test/PriorityCommandTest.py

+import CommandTest
+import PriorityCommand
+import TodoList
+
+class PriorityCommandTest(CommandTest.CommandTest):
+    def setUp(self):
+        todos = [
+            "(A) Foo",
+            "Bar",
+        ]
+
+        self.todolist = TodoList.TodoList(todos)
+
+    def test_set_prio1(self):
+        command = PriorityCommand.PriorityCommand(["1", "B"], self.todolist, self.out, self.error)
+        command.execute()
+
+        self.assertTrue(self.todolist.is_dirty())
+        self.assertEquals(self.output, "Priority changed from A to B\n(B) Foo\n")
+        self.assertEquals(self.errors, "")
+
+    def test_set_prio2(self):
+        command = PriorityCommand.PriorityCommand(["2", "Z"], self.todolist, self.out, self.error)
+        command.execute()
+
+        self.assertTrue(self.todolist.is_dirty())
+        self.assertEquals(self.output, "Priority set to Z.\n(Z) Bar\n")
+        self.assertEquals(self.errors, "")
+
+    def test_invalid1(self):
+        command = PriorityCommand.PriorityCommand(["99", "A"], self.todolist, self.out, self.error)
+        command.execute()
+
+        self.assertFalse(self.todolist.is_dirty())
+        self.assertFalse(self.output)
+        self.assertEquals(self.errors, "Invalid todo number given.\n")
+
+    def test_invalid2(self):
+        command = PriorityCommand.PriorityCommand(["1", "ZZ"], self.todolist, self.out, self.error)
+        command.execute()
+
+        self.assertFalse(self.todolist.is_dirty())
+        self.assertFalse(self.output)
+        self.assertEquals(self.errors, "Invalid priority given.\n")
+
+    def test_invalid3(self):
+        command = PriorityCommand.PriorityCommand(["A"], self.todolist, self.out, self.error)
+        command.execute()
+
+        self.assertFalse(self.todolist.is_dirty())
+        self.assertFalse(self.output)
+        self.assertEquals(self.errors, command.usage() + "\n")
+
+    def test_invalid4(self):
+        command = PriorityCommand.PriorityCommand(["1"], self.todolist, self.out, self.error)
+        command.execute()
+
+        self.assertFalse(self.todolist.is_dirty())
+        self.assertFalse(self.output)
+        self.assertEquals(self.errors, command.usage() + "\n")
+
+    def test_empty(self):
+        command = PriorityCommand.PriorityCommand([], self.todolist, self.out, self.error)
+        command.execute()
+
+        self.assertFalse(self.todolist.is_dirty())
+        self.assertFalse(self.output)
+        self.assertEquals(self.errors, command.usage() + "\n")