@Test
public void testForLedger() {

    Server server = new Server("https://horizon-testnet.stellar.org");
    URI uri = server.payments()
            .forLedger(200000000000L)
            .limit(50)
            .order(RequestBuilder.Order.ASC)
            .buildUri();
    assertEquals("https://horizon-testnet.stellar.org/ledgers/200000000000/payments?limit=50&order=asc", uri.toString());
}