@Test
  public void testListPreauthorizations() {
    PreauthorizationService srv = Paymill.getService(PreauthorizationService.class);
    List<Preauthorization> list = srv.list(0, 10);

    assertTrue(list.size() > 0);
    assertTrue(list.get(0) instanceof Preauthorization);
  }
  @Test
  public void testGetPreauthorization() {
    PreauthorizationService srv = Paymill.getService(PreauthorizationService.class);
    List<Preauthorization> list = srv.list(0, 1);
    Preauthorization tx = srv.get(list.get(0).getId());

    assertNotNull(tx);
    assertNotNull(tx.getId());
  }