fix and test for stats purge

fixes #384

engine/stats_queue.go

@@ -184,16 +184,19 @@ func (sq *StatsQueue) purgeObsoleteCdrs() {
 		}
 	}
 	if sq.conf.TimeWindow > 0 {
+		var index int
 		for i, cdr := range sq.Cdrs {
 			if time.Now().Sub(cdr.SetupTime) > sq.conf.TimeWindow {
 				sq.removeFromMetrics(cdr)
 				continue
-			} else {
-				if i > 0 {
-					sq.Cdrs = sq.Cdrs[i:]
-				}
-				break
 			}
+			index = i
+			break
+		}
+		if index > 0 {
+			sq.Cdrs = sq.Cdrs[index:]
+		} else {
+			sq.Cdrs = make([]*QCdr, 0)
 		}
 	}
 }

engine/stats_test.go

@@ -458,3 +458,25 @@ func TestStatsSaveRestoreQeue(t *testing.T) {
 		t.Errorf("Expecting %+v got: %+v", sq.Cdrs[0], recovered.Cdrs[0])
 	}
 }
+
+func TestStatsPurge(t *testing.T) {
+	sq := NewStatsQueue(&CdrStats{Metrics: []string{ASR, ACD, TCD, ACC, TCC}, TimeWindow: 30 * time.Minute})
+	cdr := &CDR{
+		AnswerTime: time.Date(2014, 7, 14, 14, 25, 0, 0, time.UTC),
+		Usage:      10 * time.Second,
+		Cost:       1,
+	}
+	sq.AppendCDR(cdr)
+	cdr.Cost = 2
+	sq.AppendCDR(cdr)
+	cdr.Cost = 3
+	sq.AppendCDR(cdr)
+	s := sq.GetStats()
+	if s[ASR] != -1 ||
+		s[ACD] != -1 ||
+		s[TCD] != -1 ||
+		s[ACC] != -1 ||
+		s[TCC] != -1 {
+		t.Errorf("Error getting stats: %+v", s)
+	}
+}