LP 353185 Core : Create chain action

2 files changed, 66 insertions, 2 deletions

diff --git a/src/sugar/tutorius/actions.py b/src/sugar/tutorius/actions.py
index 60ccd8b..7681dea 100644
--- a/src/sugar/tutorius/actions.py
+++ b/src/sugar/tutorius/actions.py
@@ -213,4 +213,19 @@ class WidgetIdentifyAction(Action):
         if self._dialog:
             self._dialog.destroy()
 
+class ChainAction(Action):
+    """Utility class to allow executing actions in a specific order"""
+    def __init__(self, *actions):
+        """ChainAction(action1, ... ) builds a chain of actions"""
+        self._actions = actions
+
+    def do(self,**kwargs):
+        """do() each action in the chain"""
+        for act in self._actions:
+            act.do(**kwargs)
+
+    def undo(self):
+        """undo() each action in the chain, starting with the last"""
+        for act in reversed(self._actions):
+            act.undo()
 
diff --git a/src/sugar/tutorius/tests/actiontests.py b/src/sugar/tutorius/tests/actiontests.py
index 5fb3d0f..9c398d4 100644
--- a/src/sugar/tutorius/tests/actiontests.py
+++ b/src/sugar/tutorius/tests/actiontests.py
@@ -24,7 +24,7 @@ The behavior of the actions must be tested here.
 import unittest
 import gtk
 
-from sugar.tutorius.actions import Action, OnceWrapper
+from sugar.tutorius.actions import *
 from sugar.tutorius.services import ObjectStore
 
 class PropertyAction(Action):
@@ -104,6 +104,55 @@ class OnceWrapperTests(unittest.TestCase):
         wrap.undo()
         assert act.undo_count == 1, "undo() should have been called only once"
 
+class ChainTester(Action):
+    def __init__(self, witness):
+        self._witness = witness
+
+    def do(self, **kwargs):
+        self._witness.append([self,"do"])
+
+    def undo(self):
+        self._witness.append([self,"undo"])
+
+class ChainActionTest(unittest.TestCase):
+    """Tester for ChainAction"""
+    def test_empty(self):
+        """If the expected empty behavior (do nothing) changes 
+        and starts throwing exceptions, this will flag it"""
+        a = ChainAction()
+        a.do()
+        a.undo()
+
+    def test_order(self):
+        witness = []
+        first = ChainTester(witness)
+        second = ChainTester(witness)
+
+        c = ChainAction(first, second)
+        assert witness == [], "Actions should not be triggered on init"""
+        c.do()
+
+        assert witness[0][0] is first, "First triggered action must be 'first'"
+        assert witness[0][1] is "do", "Action do() should be triggered"
+
+        assert witness[1][0] is second, "second triggered action must be 'second'"
+        assert witness[1][1] is "do", "Action do() should be triggered"
+
+        assert len(witness) is 2, "Two actions should give 2 do's"
+
+        #empty the witness list
+        while len(witness):
+            rm = witness.pop()
+
+        c.undo()
+        assert witness[1][0] is first, "second triggered action must be 'first'"
+        assert witness[1][1] is "undo", "Action undo() should be triggered"
+
+        assert witness[0][0] is second, "first triggered action must be 'second'"
+        assert witness[0][1] is "undo", "Action undo() should be triggered"
+
+        assert len(witness) is 2, "Two actions should give 2 undo's"
+
+        
 if __name__ == "__main__":
     unittest.main()
-