@covenance/dlc/tests/cet/repaymentCet.test.ts

Crypto and Bitcoin functions for Covenance DLC implementation

import { expect } from 'chai';
import { Transaction, Address, PrivateKey, Script, Networks, PublicKey } from '../../src/btc';
import { createDlcInitTx, createRepaymentCet } from '../../src/cet/transactions';
import { PrivKey, PubKey } from '../../src/crypto/types';
import { Point, utils } from '../../src/crypto/secp256k1';

describe('createRepaymentCet', () => {
  let borrowerKey: PrivateKey;
  let borrowerPubKey: PublicKey;
  let borrowerAddress: Address;
  
  let borrowerDlcPrivateKey: PrivKey;
  let borrowerDlcPubKey: PubKey;
  let lenderDlcPrivateKey: PrivKey;
  let lenderDlcPubKey: PubKey;
  
  let dlcUtxo: any;

  before(() => {
    borrowerKey = new PrivateKey();
    borrowerPubKey = borrowerKey.toPublicKey();
    borrowerAddress = new Address(borrowerPubKey, Networks.testnet, 'witnesspubkeyhash');

    borrowerDlcPrivateKey = utils.randomPrivateKey();
    borrowerDlcPubKey = Point.fromPrivateKey(borrowerDlcPrivateKey);

    lenderDlcPrivateKey = utils.randomPrivateKey();
    lenderDlcPubKey = Point.fromPrivateKey(lenderDlcPrivateKey);

    const collateralAmount = 100000; // 0.001 BTC
    
    const collateralUtxos = [{
      txId: 'a'.repeat(64),
      outputIndex: 0,
      satoshis: collateralAmount * 1.3,
      script: (Script as any).buildWitnessV0Out(borrowerAddress)
    }];

    const dlcInitTx = createDlcInitTx(
      collateralUtxos,
      collateralAmount,
      borrowerDlcPubKey,
      lenderDlcPubKey,
      borrowerAddress
    );
    dlcUtxo = dlcInitTx.dlcUtxo;
  });

  it('should create a valid repayment CET that returns full collateral to borrower', () => {
    const collateralAmount = dlcUtxo.satoshis;
    
    const repaymentCet = createRepaymentCet(dlcUtxo, collateralAmount, borrowerAddress);

    expect(repaymentCet).to.be.instanceOf(Transaction);
    expect(repaymentCet.inputs.length).to.equal(1);
    expect(repaymentCet.outputs.length).to.equal(1);

    expect(repaymentCet.inputs[0].prevTxId.toString('hex')).to.equal(dlcUtxo.txId);
    expect(repaymentCet.inputs[0].outputIndex).to.equal(dlcUtxo.outputIndex);

    expect(repaymentCet.outputs[0].satoshis).to.equal(collateralAmount);
    expect(repaymentCet.outputs[0].script.toString())
      .to.equal((Script as any).buildWitnessV0Out(borrowerAddress).toString());
  });
});