When new priority is the same, don't print it has changed.

test/PriorityCommandTest.py

 # Topydo - A todo.txt client written in Python.
 # Copyright (C) 2014 Bram Schoenmakers <me@bramschoenmakers.nl>
-# 
+#
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
-# 
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
-# 
+#
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
@@ -51,6 +51,13 @@ class PriorityCommandTest(CommandTest.CommandTest):
         self.assertEquals(self.output, "Priority changed from A to B\n(B) Foo\n")
         self.assertEquals(self.errors, "")
 
+    def test_set_prio4(self):
+        command = PriorityCommand.PriorityCommand(["1", "A"], self.todolist, self.out, self.error)
+        command.execute()
+
+        self.assertFalse(self.todolist.is_dirty())
+        self.assertEquals(self.output, "(A) Foo\n")
+        self.assertEquals(self.errors, "")
 
     def test_invalid1(self):
         command = PriorityCommand.PriorityCommand(["99", "A"], self.todolist, self.out, self.error)

topydo/lib/PriorityCommand.py

 # Topydo - A todo.txt client written in Python.
 # Copyright (C) 2014 Bram Schoenmakers <me@bramschoenmakers.nl>
-# 
+#
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
-# 
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
-# 
+#
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
@@ -41,9 +41,9 @@ class PriorityCommand(Command):
                 old_priority = todo.priority()
                 self.todolist.set_priority(todo, priority)
 
-                if old_priority and priority:
+                if old_priority and priority and old_priority != priority:
                     self.out("Priority changed from %s to %s" % (old_priority, priority))
-                else:
+                elif not old_priority:
                     self.out("Priority set to %s." % priority)
 
                 self.out(pretty_print(todo))