exponential.go

@@ -143,7 +143,7 @@ func (b *ExponentialBackOff) incrementCurrentInterval() {
 }
 
 // Returns a random value from the following interval:
-// 	[randomizationFactor * currentInterval, randomizationFactor * currentInterval].
+// 	[currentInterval - randomizationFactor * currentInterval, currentInterval + randomizationFactor * currentInterval].
 func getRandomValueFromInterval(randomizationFactor, random float64, currentInterval time.Duration) time.Duration {
 	var delta = randomizationFactor * float64(currentInterval)
 	var minInterval = float64(currentInterval) - delta

ticker.go

@@ -33,6 +33,9 @@ func NewTicker(b BackOff) *Ticker {
 // NewTickerWithTimer returns a new Ticker with a custom timer.
 // A default timer that uses system timer is used when nil is passed.
 func NewTickerWithTimer(b BackOff, timer Timer) *Ticker {
+	if timer == nil {
+		timer = &defaultTimer{}
+	}
 	c := make(chan time.Time)
 	t := &Ticker{
 		C:     c,

ticker_test.go

@@ -87,3 +87,10 @@ func TestTickerContext(t *testing.T) {
 		t.Errorf("invalid number of retries: %d", i)
 	}
 }
+
+func TestTickerDefaultTimer(t *testing.T) {
+	b := NewExponentialBackOff()
+	ticker := NewTickerWithTimer(b, nil)
+	// ensure a timer was actually assigned, instead of remaining as nil.
+	<-ticker.C
+}