fix test fails

pkg/net/netutil/breaker/sre_breaker.go

@@ -15,15 +15,14 @@ import (
 // sreBreaker is a sre CircuitBreaker pattern.
 type sreBreaker struct {
 	stat metric.RollingCounter
+	r    *rand.Rand
+	// rand.New(...) returns a non thread safe object
+	randLock sync.Mutex
 
 	k       float64
 	request int64
 
 	state int32
-
-	random *rand.Rand
-	// rand.New(...) returns a non thread safe object
-	randLock sync.Mutex
 }
 
 func newSRE(c *Config) Breaker {
@@ -34,11 +33,11 @@ func newSRE(c *Config) Breaker {
 	stat := metric.NewRollingCounter(counterOpts)
 	return &sreBreaker{
 		stat: stat,
+		r:    rand.New(rand.NewSource(time.Now().UnixNano())),
 
 		request: c.Request,
 		k:       c.K,
 		state:   StateClosed,
-		random:  rand.New(rand.NewSource(time.Now().UnixNano())),
 	}
 }
 
@@ -95,7 +94,7 @@ func (b *sreBreaker) MarkFailed() {
 
 func (b *sreBreaker) trueOnProba(proba float64) (truth bool) {
 	b.randLock.Lock()
-	truth = b.random.Float64() < proba
+	truth = b.r.Float64() < proba
 	b.randLock.Unlock()
 	return
 }

pkg/net/netutil/breaker/sre_breaker_test.go

@@ -29,6 +29,7 @@ func getSREBreaker() *sreBreaker {
 	stat := metric.NewRollingCounter(counterOpts)
 	return &sreBreaker{
 		stat: stat,
+		r:    rand.New(rand.NewSource(time.Now().UnixNano())),
 
 		request: 100,
 		k:       2,
@@ -151,8 +152,9 @@ func TestTrueOnProba(t *testing.T) {
 	const total = 100000
 	const epsilon = 0.05
 	var count int
+	b := getSREBreaker()
 	for i := 0; i < total; i++ {
-		if trueOnProba(proba) {
+		if b.trueOnProba(proba) {
 			count++
 		}
 	}