Edit: example

     use Psr\Http\Message\ResponseInterface;
    use Psr\Http\Message\ServerRequestInterface;

    class TransferHandler extends BaseHandler {

      public function __construct(Generator $faker, DataStorage $storage) {
       parent::__construct($faker, $storage);
      }

      public function handle(ServerRequestInterface $http_request): ResponseInterface {
       $resource_token = $http_request->getHeader('X-Resource-Token')[0];
       $account_id = $this->storage->account_id_by_resource_token[$resource_token];
       if (empty($account_id)) {
        return $this->responseInvalidResourceToken($http_request);
       }

       throw new \Exception('WIP -> store transaction data here for subsequent query, also issue notification');
      }
     }

public function testTransfer() { $juno = JunoAPISimulator::initialize($this->faker); $repo = AccountCreationRepoResolver::resolve();

     $account_id = $this->createAccountAndGetId(
      $this->merchant,
      fn(DigitalAccountRequestOperator $op) => $op->withProvider(DigitalAccountProviderSelector::JUNO())
     );

     try {
      Executor::execute(new IssueTransferByBankDetails(
       $account_id->toHex(),
       "BRL 12.42",
       $_ispb = '21018182',
       $_agencyNumber = '0001',
       $_accountNumber = '10000368021',
       $_accountType = 'CHECKING',
      ));
      $this->fail('should have thrown exception');
     } catch (\Throwable $e) {
      $this->assertEquals('WIP -> store transaction data here for subsequent query, also issue notification', $e->getPrevious()->getMessage());
     }
  }