@NonNull
  public SelectSectoralIdpStep start(@NonNull Session session) {

    return new SelectSectoralIdpStepImpl(
        selfIssuer,
        federationMasterClient,
        openIdClient,
        relyingPartyKeySupplier,
        session.callbackUri(),
        session.nonce(),
        session.codeChallengeS256(),
        session.state(),
        session.scopes());
  }
@Test
  void start() {
    var self = URI.create("https://fachdienst.example.com");
    var fedmasterClient = mock(FederationMasterClient.class);
    var openIdClient = mock(OpenIdClient.class);
    var keySupplier = mock(KeySupplier.class);

    var flow = new AuthenticationFlow(self, fedmasterClient, openIdClient, keySupplier);

    var step = flow.start(new Session(null, null, null, null, List.of()));

    assertNotNull(step);
  }