Implement reverseOrder option for GetWorkflowExecutionHistory and PollForDecisionTask

moto/swf/models/decision_task.py

@@ -16,10 +16,11 @@ class DecisionTask(object):
         # but that shouldn't be a problem for tests
         self.scheduled_at = datetime.now()
 
-    def to_full_dict(self):
+    def to_full_dict(self, reverse_order=False):
+        events = self.workflow_execution.events(reverse_order=reverse_order)
         hsh = {
             "events": [
-                evt.to_dict() for evt in self.workflow_execution.events
+                evt.to_dict() for evt in events
             ],
             "taskToken": self.task_token,
             "previousStartedEventId": self.previous_started_event_id,

moto/swf/models/workflow_execution.py

@@ -32,7 +32,7 @@ class WorkflowExecution(object):
             "openChildWorkflowExecutions": 0,
         }
         # events
-        self.events = []
+        self._events = []
         # tasks
         self.decision_tasks = []
         self.activity_tasks = []
@@ -97,13 +97,19 @@ class WorkflowExecution(object):
         hsh["openCounts"] = self.open_counts
         return hsh
 
+    def events(self, reverse_order=False):
+        if reverse_order:
+            return reversed(self._events)
+        else:
+            return self._events
+
     def next_event_id(self):
-        event_ids = [evt.event_id for evt in self.events]
+        event_ids = [evt.event_id for evt in self._events]
         return max(event_ids or [0])
 
     def _add_event(self, *args, **kwargs):
         evt = HistoryEvent(self.next_event_id(), *args, **kwargs)
-        self.events.append(evt)
+        self._events.append(evt)
         return evt
 
     def start(self):