Fix deadlock in ready test

staging/src/k8s.io/apiserver/pkg/storage/cacher/ready_test.go

@@ -18,6 +18,7 @@ package cacher
 
 import (
 	"context"
+	"sync"
 	"testing"
 	"time"
 )
@@ -81,18 +82,26 @@ func Test_newReadyRacy(t *testing.T) {
 	errCh := make(chan error, concurrency)
 	ready := newReady()
 	ready.set(false)
+
+	wg := sync.WaitGroup{}
+	wg.Add(2 * concurrency)
 	for i := 0; i < concurrency; i++ {
 		go func() {
 			errCh <- ready.wait(context.Background())
 		}()
 		go func() {
+			defer wg.Done()
 			ready.set(false)
 		}()
 		go func() {
+			defer wg.Done()
 			ready.set(true)
 		}()
 	}
+	// Last one has to be set to true.
+	wg.Wait()
 	ready.set(true)
+
 	for i := 0; i < concurrency; i++ {
 		if err := <-errCh; err != nil {
 			t.Errorf("unexpected error %v on channel %d", err, i)