@Test
public void failAddingMultipleFeeOnlySigners() {

    TransactionBuilder b = new TransactionBuilder(neow);
    exceptionRule.expect(TransactionConfigurationException.class);
    exceptionRule.expectMessage(
            new StringContains("Can't add multiple signers with the fee-only witness scope"));
    b.signers(Signer.feeOnly(account1.getScriptHash()),
            Signer.feeOnly(account2.getScriptHash()));
}