threadsafe SeededRand

util/testutil/rand.go

+package testutil
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+)
+
+var SeededRand *rand.Rand
+
+func init() {
+	SeededRand = NewSeededRand(time.Now().UTC().UnixNano())
+}
+
+func NewSeededRand(seed int64) *rand.Rand {
+	src := rand.NewSource(seed)
+	return rand.New(&LockedRandSource{src: src})
+}
+
+type LockedRandSource struct {
+	lk  sync.Mutex
+	src rand.Source
+}
+
+func (r *LockedRandSource) Int63() (n int64) {
+	r.lk.Lock()
+	n = r.src.Int63()
+	r.lk.Unlock()
+	return
+}
+
+func (r *LockedRandSource) Seed(seed int64) {
+	r.lk.Lock()
+	r.src.Seed(seed)
+	r.lk.Unlock()
+}