diff --git a/staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/customresource_discovery_controller_test.go b/staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/customresource_discovery_controller_test.go
index 4ca778e7c2b..5d279a7c47f 100644
--- a/staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/customresource_discovery_controller_test.go
+++ b/staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/customresource_discovery_controller_test.go
@@ -232,6 +232,8 @@ func (env *testEnvironment) Start(ctx context.Context) {
 	)
 
 	factory.Start(ctx.Done())
+	factory.WaitForCacheSync(ctx.Done())
+
 	go discoveryController.Run(ctx.Done(), discoverySyncedCh)
 
 	select {