withdraw test

test/GSNsupport.test.js

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+/* global artifacts, web3, contract */
+require('chai')
+  .use(require('bn-chai')(web3.utils.BN))
+  .use(require('chai-as-promised'))
+  .should()
+const fs = require('fs')
+const Web3 = require('web3')
+
+const { toBN, toHex, toChecksumAddress } = require('web3-utils')
+const { takeSnapshot, revertSnapshot, traceTransaction } = require('../lib/ganacheHelper')
+const { deployRelayHub, fundRecipient } = require('@openzeppelin/gsn-helpers')
+const { GSNDevProvider } = require('@openzeppelin/gsn-provider')
+const { ephemeral } = require('@openzeppelin/network')
+
+const Mixer = artifacts.require('./ETHMixer.sol')
+const { ETH_AMOUNT, MERKLE_TREE_HEIGHT, EMPTY_ELEMENT } = process.env
+
+const websnarkUtils = require('websnark/src/utils')
+const buildGroth16 = require('websnark/src/groth16')
+const stringifyBigInts = require('websnark/tools/stringifybigint').stringifyBigInts
+const snarkjs = require('snarkjs')
+const bigInt = snarkjs.bigInt
+const crypto = require('crypto')
+const circomlib = require('circomlib')
+const MerkleTree = require('../lib/MerkleTree')
+
+const rbigint = (nbytes) => snarkjs.bigInt.leBuff2int(crypto.randomBytes(nbytes))
+const pedersenHash = (data) => circomlib.babyJub.unpackPoint(circomlib.pedersenHash.hash(data))[0]
+
+function generateDeposit() {
+  let deposit = {
+    secret: rbigint(31),
+    nullifier: rbigint(31),
+  }
+  const preimage = Buffer.concat([deposit.nullifier.leInt2Buff(31), deposit.secret.leInt2Buff(31)])
+  deposit.commitment = pedersenHash(preimage)
+  return deposit
+}
+
+function getRandomReceiver() {
+  let receiver = rbigint(20)
+  while (toHex(receiver.toString()).length !== 42) {
+    receiver = rbigint(20)
+  }
+  return receiver
+}
+
+contract('GSN support', accounts => {
+  let mixer
+  let gsnMixer
+  let relayHubAddress
+  const sender = accounts[0]
+  const operator = accounts[0]
+  const ownerAddress = accounts[8]
+  const relayerAddress = accounts[9]
+  const levels = MERKLE_TREE_HEIGHT || 16
+  const zeroValue = EMPTY_ELEMENT || 1337
+  const value = ETH_AMOUNT || '1000000000000000000' // 1 ether
+  let snapshotId
+  let prefix = 'test'
+  let tree
+  const fee = bigInt(ETH_AMOUNT).shr(1) || bigInt(1e17)
+  const receiver = getRandomReceiver()
+  const relayer = accounts[1]
+  let groth16
+  let circuit
+  let proving_key
+
+  before(async () => {
+    tree = new MerkleTree(
+      levels,
+      zeroValue,
+      null,
+      prefix,
+    )
+    mixer = await Mixer.deployed()
+    relayHubAddress = toChecksumAddress(await deployRelayHub(web3, {
+      from: sender
+    }))
+    await fundRecipient(web3, { recipient: mixer.address, relayHubAddress })
+    await mixer.upgradeRelayHub(relayHubAddress)
+    snapshotId = await takeSnapshot()
+    groth16 = await buildGroth16()
+    circuit = require('../build/circuits/withdraw.json')
+    proving_key = fs.readFileSync('build/circuits/withdraw_proving_key.bin').buffer
+  })
+
+  describe('#constructor', () => {
+    it('should initialize', async () => {
+      const hub = await mixer.getHubAddr()
+      hub.should.be.equal(relayHubAddress)
+    })
+  })
+
+  describe('#withdrawViaRelayer', () => {
+    it.only('should work', async () => {
+      const gasPrice = toBN('20000000000')
+      const relayerTxFee = 10 // 20%
+      const deposit = generateDeposit()
+      const user = accounts[4]
+      await tree.insert(deposit.commitment)
+
+      const balanceUserBefore = await web3.eth.getBalance(user)
+
+      // Uncomment to measure gas usage
+      // let gas = await mixer.deposit.estimateGas(toBN(deposit.commitment.toString()), { value, from: user, gasPrice: '0' })
+      // console.log('deposit gas:', gas)
+      const txDeposit = await mixer.deposit(toBN(deposit.commitment.toString()), { value, from: user, gasPrice })
+      // console.log('txDeposit', txDeposit.receipt)
+      const txFee = toBN(txDeposit.receipt.gasUsed).mul(gasPrice)
+      // console.log('txFee', txFee.toString())
+      const balanceUserAfter = await web3.eth.getBalance(user)
+      balanceUserAfter.should.be.eq.BN(toBN(balanceUserBefore).sub(toBN(value).add(txFee)))
+
+      const { root, path_elements, path_index } = await tree.path(0)
+
+      // Circuit input
+      const input = stringifyBigInts({
+        // public
+        root,
+        nullifierHash: pedersenHash(deposit.nullifier.leInt2Buff(31)),
+        receiver,
+
+        // private
+        nullifier: deposit.nullifier,
+        secret: deposit.secret,
+        pathElements: path_elements,
+        pathIndex: path_index,
+      })
+
+
+      const proof = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
+      const { pi_a, pi_b, pi_c, publicSignals } = websnarkUtils.toSolidityInput(proof)
+
+      const balanceMixerBefore = await web3.eth.getBalance(mixer.address)
+      const balanceHubBefore = await web3.eth.getBalance(relayHubAddress)
+      const balanceRelayerBefore = await web3.eth.getBalance(relayerAddress)
+      const balanceRelayerOwnerBefore = await web3.eth.getBalance(ownerAddress)
+      const balanceRecieverBefore = await web3.eth.getBalance(toHex(receiver.toString()))
+      let isSpent = await mixer.isSpent(input.nullifierHash.toString(16).padStart(66, '0x00000'))
+      isSpent.should.be.equal(false)
+
+      const account = ephemeral()
+      const provider = new GSNDevProvider('http://localhost:8545', {
+        signKey: account,
+        ownerAddress,
+        relayerAddress,
+        verbose: true,
+        txFee: relayerTxFee
+      })
+      // console.log('relayerAddress', relayerAddress)
+      const gsnWeb3 = new Web3(provider, null, { transactionConfirmationBlocks: 1 })
+      gsnMixer = new gsnWeb3.eth.Contract(mixer.abi, mixer.address)
+      const tx = await gsnMixer.methods.withdrawViaRelayer(pi_a, pi_b, pi_c, publicSignals).send({
+        from: account.address,
+        gas: 3e6,
+        gasPrice,
+        value: 0
+      })
+      // console.log('tx', tx)
+      const debug = await traceTransaction(tx.transactionHash)
+      console.log('debug', debug.result.structLogs)
+      const { events, gasUsed } = tx
+      // console.log('events', events, gasUsed)
+      const balanceMixerAfter = await web3.eth.getBalance(mixer.address)
+      const balanceHubAfter = await web3.eth.getBalance(relayHubAddress)
+      const balanceRelayerAfter = await web3.eth.getBalance(relayerAddress)
+      const balanceRelayerOwnerAfter = await web3.eth.getBalance(ownerAddress)
+      const balanceRecieverAfter = await web3.eth.getBalance(toHex(receiver.toString()))
+      console.log('balanceMixerBefore, balanceMixerAfter', balanceMixerBefore.toString(), balanceMixerAfter.toString())
+      console.log('balanceRecieverBefore, balanceRecieverAfter', balanceRecieverBefore.toString(), balanceRecieverAfter.toString())
+      console.log('balanceHubBefore, balanceHubAfter', balanceHubBefore.toString(), balanceHubAfter.toString())
+      console.log('balanceRelayerBefore, balanceRelayerAfter', balanceRelayerBefore.toString(), balanceRelayerAfter.toString(), toBN(balanceRelayerBefore).sub(toBN(balanceRelayerAfter)).toString())
+      console.log('balanceRelayerOwnerBefore, balanceRelayerOwnerAfter', balanceRelayerOwnerBefore.toString(), balanceRelayerOwnerAfter.toString())
+      // balanceMixerAfter.should.be.eq.BN(toBN(balanceMixerBefore).sub(toBN(value)))
+      const networkFee = toBN(gasUsed).mul(gasPrice)
+      const chargedFee = networkFee.add(networkFee.div(toBN(relayerTxFee)))
+      console.log('networkFee, calc chargedFee', networkFee.toString(), chargedFee.toString())
+      // const fee = toBN(value).sub(toBN(balanceRecieverAfter))
+      // console.log('actual charged fee', fee.toString())
+      balanceRelayerAfter.should.be.eq.BN(toBN(balanceRelayerBefore).sub(networkFee))
+      // balanceRelayerOwnerAfter.should.be.eq.BN(toBN(balanceRelayerOwnerBefore))
+      // balanceRecieverAfter.should.be.gt.BN(toBN(balanceRecieverBefore))
+      // balanceHubAfter.should.be.eq.BN(toBN(balanceHubBefore).add(fee))
+
+      // console.log('events.Withdraw.returnValues.nullifierHash', events.Withdraw.returnValues.nullifierHash.toString(), input.nullifierHash.toString())
+      // events.Withdraw.returnValues.nullifierHash.should.be.eq.BN(toBN(input.nullifierHash.toString()))
+      events.Withdraw.returnValues.relayer.should.be.eq.BN(relayerAddress)
+      events.Withdraw.returnValues.to.should.be.eq.BN(toHex(receiver.toString()))
+
+      isSpent = await mixer.isSpent(input.nullifierHash.toString(16).padStart(66, '0x00000'))
+      isSpent.should.be.equal(true)
+    })
+  })
+
+  afterEach(async () => {
+    await revertSnapshot(snapshotId.result)
+    // eslint-disable-next-line require-atomic-updates
+    snapshotId = await takeSnapshot()
+    tree = new MerkleTree(
+      levels,
+      zeroValue,
+      null,
+      prefix,
+    )
+  })
+})