make sure the test is good

pkg/wrapper/exponentialBackoff_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"github.com/alaingilbert/clockwork"
 	"github.com/magiconair/properties/assert"
+	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -12,6 +13,8 @@ import (
 func TestExponentialBackoff_Wait(t *testing.T) {
 	var counter uint32
 	clock := clockwork.NewFakeClock()
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
 	go func() {
 		clock.BlockUntil(1)
 		clock.Advance(1000 * time.Millisecond)
@@ -23,12 +26,14 @@ func TestExponentialBackoff_Wait(t *testing.T) {
 		clock.Advance(4000 * time.Millisecond)
 		clock.BlockUntil(0)
 		atomic.AddUint32(&counter, 1)
+		wg.Done()
 	}()
 	e := NewExponentialBackoff(context.Background(), 60)
 	e.SetClock(clock)
 	e.Wait() // First time has no wait
 	e.Wait() // Wait 1s
 	e.Wait() // Wait 2s
 	e.Wait() // Wait 4s
+	wg.Wait()
 	assert.Equal(t, uint32(1), atomic.LoadUint32(&counter))
 }