code: func CreateCACert(t *testing.T) (*x509.Certificate, crypto.Signer) {
  	certCfg := &certutil.Config{CommonName: "kubernetes"}
  	cert, key, err := pkiutil.NewCertificateAuthority(certCfg)
  	if err != nil {
  		t.Fatalf("couldn't create CA: %v", err)
  	}
  	return cert, key
  }
docs: // CreateCACert creates a generic CA cert.