Update randx to fix race conditions (#433)

fix/auto_timestamps_off_test.go

@@ -31,10 +31,8 @@ func Test_AutoTimestampsOff(t *testing.T) {
 			cleaned := re.ReplaceAllString(expected, "")
 			cleanedPatched := re.ReplaceAllString(patched, "")
 
-
 			rr.Equal(cleaned, cleanedPatched)
 
-
 		})
 		return nil
 	})

internal/randx/randx.go

@@ -2,9 +2,29 @@ package randx
 
 import (
 	"math/rand"
+	"sync"
 	"time"
 )
 
 func init() {
 	rand.Seed(time.Now().UnixNano())
 }
+
+type safeSrc struct {
+	src  rand.Source
+	moot sync.Mutex
+}
+
+func (s *safeSrc) Int63() int64 {
+	s.moot.Lock()
+	n := s.src.Int63()
+	s.moot.Unlock()
+	return n
+}
+
+func newSafeSrc(s rand.Source) *safeSrc {
+	return &safeSrc{
+		src:  s,
+		moot: sync.Mutex{},
+	}
+}

internal/randx/string.go

@@ -14,8 +14,9 @@ const (
 	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
 )
 
-var src = rand.NewSource(time.Now().UnixNano())
+var src = newSafeSrc(rand.NewSource(time.Now().UnixNano()))
 
+// String generates a random string with the given length.
 func String(n int) string {
 	b := make([]byte, n)
 	// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!

internal/randx/string_test.go

@@ -2,6 +2,7 @@ package randx
 
 import (
 	"math/rand"
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -16,3 +17,18 @@ func Test_String(t *testing.T) {
 	r.Len(String(5), 5)
 	r.Len(String(50), 50)
 }
+
+func Test_String_Parallel(t *testing.T) {
+	wg := sync.WaitGroup{}
+	wg.Add(100)
+	for i := 0; i < 100; i++ {
+		go func() {
+			id := String(30)
+			if len(id) != 30 {
+				t.FailNow()
+			}
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+}