func runsslserver(t *testing.T, server *smtpd.Server) (addr string, closer func()) { cert, err := tls.X509KeyPair(localhostCert, localhostKey) if err != nil { t.Fatalf("Cert load failed: %v", err) } server.TLSConfig = &tls.Config{ Certificates: []tls.Certificate{cert}, } return runserver(t, server) }