@VisibleForTesting
  void checkDestinationFolderField( String realDestinationFoldernameFieldName, SFTPPutData data ) throws KettleStepException {
    realDestinationFoldernameFieldName = environmentSubstitute( realDestinationFoldernameFieldName );
    if ( Utils.isEmpty( realDestinationFoldernameFieldName ) ) {
      throw new KettleStepException( BaseMessages.getString(
        PKG, "SFTPPut.Log.DestinatFolderNameFieldNameMissing" ) );
    }

    data.indexOfMoveToFolderFieldName = getInputRowMeta().indexOfValue( realDestinationFoldernameFieldName );
    if ( data.indexOfMoveToFolderFieldName == -1 ) {
      // move to folder field is missing
      throw new KettleStepException( BaseMessages.getString(
        PKG, "SFTPPut.Error.CanNotFindField", realDestinationFoldernameFieldName ) );
    }
  }
@Test( expected = KettleStepException.class )
  public void checkDestinationFolderField_NameIsBlank() throws Exception {
    SFTPPutData data = new SFTPPutData();
    step.checkDestinationFolderField( "", data );
  }