@Test(expected = IllegalArgumentException.class)
public void testInvalidSortOrder() {

  Context context = new Context();
  context.put(SpoolDirectorySourceConfigurationConstants.SPOOL_DIRECTORY,
      tmpDir.getAbsolutePath());
  context.put(SpoolDirectorySourceConfigurationConstants.CONSUME_ORDER,
      "undefined");
  Configurables.configure(source, context);
}