if !os.IsNotExist(err) {
			return "", "", err
		}
	}
	if err := os.Rename(writeDir, targetDir); err != nil {
		return "", "", err
	}

	return certPath, keyPath, nil
}

func TestKubeletServerCertificateFromFiles(t *testing.T) {
	// test two common ways of certificate file updates:
	// 1. delete and write the cert and key files directly