Update correctly the EventCost in case of refund

engine/eventcost.go

@@ -607,8 +607,10 @@ func (ec *EventCost) Trim(atUsage time.Duration) (srplusEC *EventCost, err error
 		return // no trim
 	}
 	if atUsage == 0 {
-		srplusEC = ec
-		ec = NewBareEventCost()
+		//clone the event because we need to overwrite ec
+		srplusEC = ec.Clone()
+		// modify the value of ec
+		*ec = *NewBareEventCost()
 		ec.CGRID = srplusEC.CGRID
 		ec.RunID = srplusEC.RunID
 		ec.StartTime = srplusEC.StartTime

engine/eventcost_test.go

@@ -991,15 +991,22 @@ func TestECTrimZeroAndFull(t *testing.T) {
 	}
 	eFullSrpls := testEC.Clone()
 	eFullSrpls.Usage = utils.DurationPointer(time.Duration(10 * time.Minute))
-	eFullSrpls.Charges[0].usage = utils.DurationPointer(time.Duration(1 * time.Minute))
-	eFullSrpls.Charges[1].usage = utils.DurationPointer(time.Duration(1 * time.Minute))
-	eFullSrpls.Charges[2].usage = utils.DurationPointer(time.Duration(1 * time.Minute))
 	if srplsEC, err := ec.Trim(time.Duration(0)); err != nil {
 		t.Error(err)
 	} else if !reflect.DeepEqual(eFullSrpls, srplsEC) {
 		t.Errorf("\tExpecting: %s,\n\treceived: %s",
 			utils.ToJSON(eFullSrpls), utils.ToJSON(srplsEC))
 	}
+	//verify the event cost
+	newEc := NewBareEventCost()
+	newEc.CGRID = eFullSrpls.CGRID
+	newEc.RunID = eFullSrpls.RunID
+	newEc.StartTime = eFullSrpls.StartTime
+	newEc.AccountSummary = eFullSrpls.AccountSummary.Clone()
+	if !reflect.DeepEqual(newEc, ec) {
+		t.Errorf("\tExpecting: %s,\n\treceived: %s",
+			utils.ToJSON(newEc), utils.ToJSON(ec))
+	}
 }
 
 func TestECTrimMiddle1(t *testing.T) {

sessions/sessions.go

@@ -1451,7 +1451,6 @@ func (sS *SessionS) endSession(s *Session, tUsage, lastUsage *time.Duration, aTi
 							"<%s> failed refunding session: <%s>, srIdx: <%d>, error: <%s>",
 							utils.SessionS, s.CGRID, sRunIdx, err.Error()))
 				}
-				// FixMe: make sure refund is reflected inside EventCost
 			}
 			// set cost fields
 			sr.Event[utils.Cost] = sr.EventCost.GetCost()