more robust tests on Machine now that it can deliver on interruption

dream/simulation/Machine.py

@@ -753,6 +753,8 @@ class Machine(CoreObject):
             # if there was no available receiver, get into blocking control
                                 
                 while 1:
+                    if not len(self.getActiveObjectQueue()):
+                        break
                     self.expectedSignals['interruptionStart']=1
                     self.expectedSignals['canDispose']=1
                     self.timeLastBlockageStarted=self.env.now       # blockage is starting
@@ -818,14 +820,13 @@ class Machine(CoreObject):
                     #       the preceding machine gets the canDispose signal which is actually useless, is emptied by the following station
                     #       and then cannot exit an infinite loop.
                     # notify that the station waits the entity to be removed
+                    activeObjectQueue=self.getActiveObjectQueue()
+                    if len(activeObjectQueue): 
                         self.waitEntityRemoval=True
                         self.printTrace(self.id, waitEvent='(entityRemoved)')
                         
                         self.expectedSignals['entityRemoved']=1
-                    
                         yield self.entityRemoved
-
-                    
                         transmitter, eventTime=self.entityRemoved.value
                         self.printTrace(self.id, entityRemoved=eventTime)
                         assert eventTime==self.env.now,'entityRemoved event activated earlier than received'
@@ -923,16 +924,12 @@ class Machine(CoreObject):
         # the machine is currently performing nothing
         self.currentlyPerforming=None
         activeObjectQueue=self.Res.users
+        if len(activeObjectQueue):
             activeEntity=activeObjectQueue[0]
             self.printTrace(activeEntity.name, interrupted=self.objName)                                    
-        # if the interrupt occurred while processing an entity
-        if not self.waitToDispose:
-            # output to trace that the Machine (self.objName) got interrupted           
-            try:                                                       
             self.outputTrace(activeObjectQueue[0].name, "Interrupted at "+self.objName)
-            except IndexError:
-                pass
             # recalculate the processing time left tinM
+            if self.timeLastOperationStarted:
                 self.tinM=self.tinM-(self.env.now-self.timeLastOperationStarted)
                 if(self.tinM==0):       # sometimes the failure may happen exactly at the time that the processing would finish
                                         # this may produce disagreement with the simul8 because in both SimPy and Simul8
@@ -957,12 +954,14 @@ class Machine(CoreObject):
     # =======================================================================    
     def postInterruptionActions(self):
         activeObjectQueue=self.Res.users
+        if len(activeObjectQueue):
             activeEntity=activeObjectQueue[0]
         # if the machine returns from an failure while processing an entity
         if not self.waitToDispose:
             # use the timers to count the time that Machine is down and related
             self.timeLastFailureEnded=self.env.now                                 # set the timeLastFailureEnded
             # output to trace that the Machine self.objName was passivated for the current failure time
+            if len(activeObjectQueue):
                 self.outputTrace(activeObjectQueue[0].name, "passivated in "+self.objName+" for "+str(self.env.now-self.breakTime))
         # when a machine returns from failure while trying to deliver an entity
         else: