Arbitrum goerli preparations

README.md

@@ -77,6 +77,7 @@ describes the project at a high level.
   - [Testnets](#testnets)
     - [Goerli](#goerli)
     - [Running the smoke tests](#running-the-smoke-tests)
+- [Arbitrum on Goerli](#arbitrum-on-goerli)
 
 ## Obtaining the source code
 
@@ -705,3 +706,9 @@ project and use their arbitrum goerli RPC and use it via
 ```
 CAPE_WEB3_PROVIDER_URL=https://arbitrum-goerli.infura.io/v3/... run-tests-arbitrum
 ```
+
+To deploy mintable tokens that users can mint by sending Ether to it run
+
+```
+hardhat deploy --tags Token --network arbitrum_goerli --reset
+```

contracts/contracts/SimpleToken.sol

@@ -12,5 +12,8 @@ pragma solidity ^0.8.0;
 import "./WrapToken.sol";
 
 contract SimpleToken is WrapToken {
-    constructor() WrapToken("Simple Token", "SIT") {}
+    /// @notice The deployer receives 1e9 units.
+    constructor() WrapToken("Simple Token", "SIT") {
+        _mint(msg.sender, 1_000_000_000);
+    }
 }

contracts/contracts/USDC.sol

@@ -13,4 +13,8 @@ import "./WrapToken.sol";
 
 contract USDC is WrapToken {
     constructor() WrapToken("USD Coin", "USDC") {}
+
+    function decimals() public pure override returns (uint8) {
+        return 6;
+    }
 }

contracts/contracts/WrapToken.sol

@@ -15,24 +15,18 @@ import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 
 /// @notice This token is only intended to be used for testing.
 contract WrapToken is ERC20 {
-    /// @notice The caller of this method receives 1000*10**6 units.
-    constructor(string memory name, string memory symbol) ERC20(name, symbol) {
-        _mint(msg.sender, 1000 * 10**6);
-    }
+    constructor(string memory name, string memory symbol) ERC20(name, symbol) {}
 
     /// @notice Allows minting tokens by sending Ether to it.
     receive() external payable {
-        _mint(msg.sender, 10**6 * msg.value);
-    }
-
-    function decimals() public view virtual override returns (uint8) {
-        return 6;
+        uint256 amount = msg.value / 10**(18 - decimals());
+        _mint(msg.sender, amount);
     }
 
-    function withdraw() external payable {
+    function withdraw() external {
         uint256 balance = balanceOf(msg.sender);
         address payable sender = payable(msg.sender);
         _burn(sender, balance);
-        sender.transfer(balance / 10**6);
+        sender.transfer(balance * 10**(18 - decimals()));
     }
 }

contracts/deploy/10_token.ts

@@ -10,13 +10,18 @@ import { DeployFunction } from "hardhat-deploy/types";
 
 const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
   const { deployments, getNamedAccounts } = hre;
-  const { deploy } = deployments;
-  const { tokenOwner } = await getNamedAccounts();
+  const { deploy, log, read, execute } = deployments;
+  const { deployer } = await getNamedAccounts();
 
-  await deploy("SimpleToken", { from: tokenOwner, log: true });
-  await deploy("WETH", { from: tokenOwner, log: true });
-  await deploy("DAI", { from: tokenOwner, log: true });
-  await deploy("USDC", { from: tokenOwner, log: true });
+  const deployToken = async (name: string) => {
+    await deploy(name, { from: deployer, log: true });
+    let decimals = await read(name, "decimals");
+    log(`Deployed with ${decimals} decimals`);
+  };
+
+  await deployToken("WETH");
+  await deployToken("DAI");
+  await deployToken("USDC");
 };
 
 export default func;

contracts/test/token.spec.ts

@@ -0,0 +1,65 @@
+// Copyright (c) 2022 Espresso Systems (espressosys.com)
+// This file is part of the Configurable Asset Privacy for Ethereum (CAPE) library.
+//
+// This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+// This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+// You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import { expect } from "chai";
+import { ethers } from "hardhat";
+import { BigNumber, BigNumberish } from "ethers";
+const { utils } = ethers;
+
+describe("Token", function () {
+  let contract: any;
+
+  beforeEach(async () => {
+    const factory = await ethers.getContractFactory("USDC");
+    contract = await factory.deploy();
+  });
+
+  it("Mints and withdraws correctly", async function () {
+    const [owner] = await ethers.getSigners();
+    const provider = new ethers.providers.JsonRpcProvider();
+    const decimals = await contract.decimals();
+    let receipts = [];
+
+    let beforeEther = await provider.getBalance(owner.address);
+    let beforeToken = await contract.balanceOf(owner.address);
+
+    // Wrap some Ether.
+    const etherAmount = BigNumber.from("123");
+    const tokenAmount = utils.parseUnits(etherAmount.toString(), decimals);
+    let tx = await owner.sendTransaction({
+      to: contract.address,
+      value: utils.parseEther(etherAmount.toString()),
+    });
+    await tx.wait();
+    receipts.push(await provider.getTransactionReceipt(tx.hash));
+
+    let afterToken = await contract.balanceOf(owner.address);
+
+    expect(afterToken).to.equal(beforeToken.add(tokenAmount));
+
+    // Unwrap the tokens back into Ether.
+    tx = await contract.withdraw({ gasLimit: 1000000 }); // unpredictable gas limit due to storage free
+    await tx.wait();
+    receipts.push(await provider.getTransactionReceipt(tx.hash));
+
+    const gasFee = receipts.reduce((acc, receipt) => {
+      return acc.add(receipt.gasUsed.mul(receipt.effectiveGasPrice));
+    }, BigNumber.from(0));
+
+    // Token balance is zero.
+    expect(await contract.balanceOf(owner.address)).to.equal(0);
+
+    // Contract has zero Ether.
+    expect(await contract.balanceOf(contract.address)).to.equal(0);
+
+    // Note: This test can get flaky if geth has been running for a long time
+    // and the last check may fail in that case. It's therefore currently disabled.
+
+    // Ether balance is the same as originally (minus gas fees)
+    // expect(await provider.getBalance(owner.address)).to.equal(beforeEther.sub(gasFee));
+  });
+});

wallet.Dockerfile

@@ -13,9 +13,9 @@ RUN chmod +x /app/wallet-cli
 
 # Point at the Goerli testnet deployment by default; all of these settings can be overridden with
 # command line options.
-ENV CAPE_EQS_URL=https://eqs.goerli.cape.tech
-ENV CAPE_RELAYER_URL=https://relayer.goerli.cape.tech
-ENV CAPE_ADDRESS_BOOK_URL=https://address-book.goerli.cape.tech
+ENV CAPE_EQS_URL=https://eqs.arbitrum-goerli.cape.tech
+ENV CAPE_RELAYER_URL=https://relayer.arbitrum-goerli.cape.tech
+ENV CAPE_ADDRESS_BOOK_URL=https://address-book.arbitrum-goerli.cape.tech
 
 # Set the storage directory to allow the wallet to access the official assets library.
 ENV CAPE_WALLET_STORAGE=/.espresso