@Test(expected = Exception.class)
public void testSendNullTransactionThrowsException() throws Exception {

    try {
        orderer = hfclient.newOrderer(ORDERER_NAME, "grpc://localhost:5151");
    } catch (InvalidArgumentException e) {
        Assert.fail("Failed to create new orderer: " + e);
    }
    orderer.sendTransaction(null);
    Assert.fail("Transaction should not be null.");
}