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openzeppelin-contracts/test/token/ERC20/extensions/ERC4626.test.js

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const { ethers } = require('hardhat');
const { expect } = require('chai');
const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
const { PANIC_CODES } = require('@nomicfoundation/hardhat-chai-matchers/panic');
const { Enum } = require('../../../helpers/enums');
const name = 'My Token';
const symbol = 'MTKN';
const decimals = 18n;
async function fixture() {
const [holder, recipient, spender, other, ...accounts] = await ethers.getSigners();
return { holder, recipient, spender, other, accounts };
}
describe('ERC4626', function () {
beforeEach(async function () {
Object.assign(this, await loadFixture(fixture));
});
it('inherit decimals if from asset', async function () {
for (const decimals of [0n, 9n, 12n, 18n, 36n]) {
const token = await ethers.deployContract('$ERC20DecimalsMock', ['', '', decimals]);
const vault = await ethers.deployContract('$ERC4626', ['', '', token]);
expect(await vault.decimals()).to.equal(decimals);
}
});
it('asset has not yet been created', async function () {
const vault = await ethers.deployContract('$ERC4626', ['', '', this.other.address]);
expect(await vault.decimals()).to.equal(decimals);
});
it('underlying excess decimals', async function () {
const token = await ethers.deployContract('$ERC20ExcessDecimalsMock');
const vault = await ethers.deployContract('$ERC4626', ['', '', token]);
expect(await vault.decimals()).to.equal(decimals);
});
it('decimals overflow', async function () {
for (const offset of [243n, 250n, 255n]) {
const token = await ethers.deployContract('$ERC20DecimalsMock', ['', '', decimals]);
const vault = await ethers.deployContract('$ERC4626OffsetMock', ['', '', token, offset]);
await expect(vault.decimals()).to.be.revertedWithPanic(PANIC_CODES.ARITHMETIC_UNDER_OR_OVERFLOW);
}
});
describe('reentrancy', async function () {
const reenterType = Enum('No', 'Before', 'After');
const value = 1_000_000_000_000_000_000n;
const reenterValue = 1_000_000_000n;
beforeEach(async function () {
// Use offset 1 so the rate is not 1:1 and we can't possibly confuse assets and shares
const token = await ethers.deployContract('$ERC20Reentrant');
const vault = await ethers.deployContract('$ERC4626OffsetMock', ['', '', token, 1n]);
// Funds and approval for tests
await token.$_mint(this.holder, value);
await token.$_mint(this.other, value);
await token.$_approve(this.holder, vault, ethers.MaxUint256);
await token.$_approve(this.other, vault, ethers.MaxUint256);
await token.$_approve(token, vault, ethers.MaxUint256);
Object.assign(this, { token, vault });
});
// During a `_deposit`, the vault does `transferFrom(depositor, vault, assets)` -> `_mint(receiver, shares)`
// such that a reentrancy BEFORE the transfer guarantees the price is kept the same.
// If the order of transfer -> mint is changed to mint -> transfer, the reentrancy could be triggered on an
// intermediate state in which the ratio of assets/shares has been decreased (more shares than assets).
it('correct share price is observed during reentrancy before deposit', async function () {
// mint token for deposit
await this.token.$_mint(this.token, reenterValue);
// Schedules a reentrancy from the token contract
await this.token.scheduleReenter(
reenterType.Before,
this.vault,
this.vault.interface.encodeFunctionData('deposit', [reenterValue, this.holder.address]),
);
// Initial share price
const sharesForDeposit = await this.vault.previewDeposit(value);
const sharesForReenter = await this.vault.previewDeposit(reenterValue);
await expect(this.vault.connect(this.holder).deposit(value, this.holder))
// Deposit normally, reentering before the internal `_update`
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.holder, value, sharesForDeposit)
// Reentrant deposit event → uses the same price
.to.emit(this.vault, 'Deposit')
.withArgs(this.token, this.holder, reenterValue, sharesForReenter);
// Assert prices is kept
expect(await this.vault.previewDeposit(value)).to.equal(sharesForDeposit);
});
// During a `_withdraw`, the vault does `_burn(owner, shares)` -> `transfer(receiver, assets)`
// such that a reentrancy AFTER the transfer guarantees the price is kept the same.
// If the order of burn -> transfer is changed to transfer -> burn, the reentrancy could be triggered on an
// intermediate state in which the ratio of shares/assets has been decreased (more assets than shares).
it('correct share price is observed during reentrancy after withdraw', async function () {
// Deposit into the vault: holder gets `value` share, token.address gets `reenterValue` shares
await this.vault.connect(this.holder).deposit(value, this.holder);
await this.vault.connect(this.other).deposit(reenterValue, this.token);
// Schedules a reentrancy from the token contract
await this.token.scheduleReenter(
reenterType.After,
this.vault,
this.vault.interface.encodeFunctionData('withdraw', [reenterValue, this.holder.address, this.token.target]),
);
// Initial share price
const sharesForWithdraw = await this.vault.previewWithdraw(value);
const sharesForReenter = await this.vault.previewWithdraw(reenterValue);
// Do withdraw normally, triggering the _afterTokenTransfer hook
await expect(this.vault.connect(this.holder).withdraw(value, this.holder, this.holder))
// Main withdraw event
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.holder, this.holder, value, sharesForWithdraw)
// Reentrant withdraw event → uses the same price
.to.emit(this.vault, 'Withdraw')
.withArgs(this.token, this.holder, this.token, reenterValue, sharesForReenter);
// Assert price is kept
expect(await this.vault.previewWithdraw(value)).to.equal(sharesForWithdraw);
});
// Donate newly minted tokens to the vault during the reentracy causes the share price to increase.
// Still, the deposit that trigger the reentracy is not affected and get the previewed price.
// Further deposits will get a different price (getting fewer shares for the same value of assets)
it('share price change during reentracy does not affect deposit', async function () {
// Schedules a reentrancy from the token contract that mess up the share price
await this.token.scheduleReenter(
reenterType.Before,
this.token,
this.token.interface.encodeFunctionData('$_mint', [this.vault.target, reenterValue]),
);
// Price before
const sharesBefore = await this.vault.previewDeposit(value);
// Deposit, reentering before the internal `_update`
await expect(this.vault.connect(this.holder).deposit(value, this.holder))
// Price is as previewed
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.holder, value, sharesBefore);
// Price was modified during reentrancy
expect(await this.vault.previewDeposit(value)).to.lt(sharesBefore);
});
// Burn some tokens from the vault during the reentracy causes the share price to drop.
// Still, the withdraw that trigger the reentracy is not affected and get the previewed price.
// Further withdraw will get a different price (needing more shares for the same value of assets)
it('share price change during reentracy does not affect withdraw', async function () {
await this.vault.connect(this.holder).deposit(value, this.holder);
await this.vault.connect(this.other).deposit(value, this.other);
// Schedules a reentrancy from the token contract that mess up the share price
await this.token.scheduleReenter(
reenterType.After,
this.token,
this.token.interface.encodeFunctionData('$_burn', [this.vault.target, reenterValue]),
);
// Price before
const sharesBefore = await this.vault.previewWithdraw(value);
// Withdraw, triggering the _afterTokenTransfer hook
await expect(this.vault.connect(this.holder).withdraw(value, this.holder, this.holder))
// Price is as previewed
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.holder, this.holder, value, sharesBefore);
// Price was modified during reentrancy
expect(await this.vault.previewWithdraw(value)).to.gt(sharesBefore);
});
});
describe('limits', async function () {
beforeEach(async function () {
const token = await ethers.deployContract('$ERC20DecimalsMock', [name, symbol, decimals]);
const vault = await ethers.deployContract('$ERC4626LimitsMock', ['', '', token]);
Object.assign(this, { token, vault });
});
it('reverts on deposit() above max deposit', async function () {
const maxDeposit = await this.vault.maxDeposit(this.holder);
await expect(this.vault.connect(this.holder).deposit(maxDeposit + 1n, this.recipient))
.to.be.revertedWithCustomError(this.vault, 'ERC4626ExceededMaxDeposit')
.withArgs(this.recipient, maxDeposit + 1n, maxDeposit);
});
it('reverts on mint() above max mint', async function () {
const maxMint = await this.vault.maxMint(this.holder);
await expect(this.vault.connect(this.holder).mint(maxMint + 1n, this.recipient))
.to.be.revertedWithCustomError(this.vault, 'ERC4626ExceededMaxMint')
.withArgs(this.recipient, maxMint + 1n, maxMint);
});
it('reverts on withdraw() above max withdraw', async function () {
const maxWithdraw = await this.vault.maxWithdraw(this.holder);
await expect(this.vault.connect(this.holder).withdraw(maxWithdraw + 1n, this.recipient, this.holder))
.to.be.revertedWithCustomError(this.vault, 'ERC4626ExceededMaxWithdraw')
.withArgs(this.holder, maxWithdraw + 1n, maxWithdraw);
});
it('reverts on redeem() above max redeem', async function () {
const maxRedeem = await this.vault.maxRedeem(this.holder);
await expect(this.vault.connect(this.holder).redeem(maxRedeem + 1n, this.recipient, this.holder))
.to.be.revertedWithCustomError(this.vault, 'ERC4626ExceededMaxRedeem')
.withArgs(this.holder, maxRedeem + 1n, maxRedeem);
});
});
for (const offset of [0n, 6n, 18n]) {
const parseToken = token => token * 10n ** decimals;
const parseShare = share => share * 10n ** (decimals + offset);
const virtualAssets = 1n;
const virtualShares = 10n ** offset;
describe(`offset: ${offset}`, function () {
beforeEach(async function () {
const token = await ethers.deployContract('$ERC20DecimalsMock', [name, symbol, decimals]);
const vault = await ethers.deployContract('$ERC4626OffsetMock', [name + ' Vault', symbol + 'V', token, offset]);
await token.$_mint(this.holder, ethers.MaxUint256 / 2n); // 50% of maximum
await token.$_approve(this.holder, vault, ethers.MaxUint256);
await vault.$_approve(this.holder, this.spender, ethers.MaxUint256);
Object.assign(this, { token, vault });
});
it('metadata', async function () {
expect(await this.vault.name()).to.equal(name + ' Vault');
expect(await this.vault.symbol()).to.equal(symbol + 'V');
expect(await this.vault.decimals()).to.equal(decimals + offset);
expect(await this.vault.asset()).to.equal(this.token);
});
describe('empty vault: no assets & no shares', function () {
it('status', async function () {
expect(await this.vault.totalAssets()).to.equal(0n);
});
it('deposit', async function () {
expect(await this.vault.maxDeposit(this.holder)).to.equal(ethers.MaxUint256);
expect(await this.vault.previewDeposit(parseToken(1n))).to.equal(parseShare(1n));
const tx = this.vault.connect(this.holder).deposit(parseToken(1n), this.recipient);
await expect(tx).to.changeTokenBalances(
this.token,
[this.holder, this.vault],
[-parseToken(1n), parseToken(1n)],
);
await expect(tx).to.changeTokenBalance(this.vault, this.recipient, parseShare(1n));
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.holder, this.vault, parseToken(1n))
.to.emit(this.vault, 'Transfer')
.withArgs(ethers.ZeroAddress, this.recipient, parseShare(1n))
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.recipient, parseToken(1n), parseShare(1n));
});
it('mint', async function () {
expect(await this.vault.maxMint(this.holder)).to.equal(ethers.MaxUint256);
expect(await this.vault.previewMint(parseShare(1n))).to.equal(parseToken(1n));
const tx = this.vault.connect(this.holder).mint(parseShare(1n), this.recipient);
await expect(tx).to.changeTokenBalances(
this.token,
[this.holder, this.vault],
[-parseToken(1n), parseToken(1n)],
);
await expect(tx).to.changeTokenBalance(this.vault, this.recipient, parseShare(1n));
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.holder, this.vault, parseToken(1n))
.to.emit(this.vault, 'Transfer')
.withArgs(ethers.ZeroAddress, this.recipient, parseShare(1n))
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.recipient, parseToken(1n), parseShare(1n));
});
it('withdraw', async function () {
expect(await this.vault.maxWithdraw(this.holder)).to.equal(0n);
expect(await this.vault.previewWithdraw(0n)).to.equal(0n);
const tx = this.vault.connect(this.holder).withdraw(0n, this.recipient, this.holder);
await expect(tx).to.changeTokenBalances(this.token, [this.vault, this.recipient], [0n, 0n]);
await expect(tx).to.changeTokenBalance(this.vault, this.holder, 0n);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.recipient, 0n)
.to.emit(this.vault, 'Transfer')
.withArgs(this.holder, ethers.ZeroAddress, 0n)
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.recipient, this.holder, 0n, 0n);
});
it('redeem', async function () {
expect(await this.vault.maxRedeem(this.holder)).to.equal(0n);
expect(await this.vault.previewRedeem(0n)).to.equal(0n);
const tx = this.vault.connect(this.holder).redeem(0n, this.recipient, this.holder);
await expect(tx).to.changeTokenBalances(this.token, [this.vault, this.recipient], [0n, 0n]);
await expect(tx).to.changeTokenBalance(this.vault, this.holder, 0n);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.recipient, 0n)
.to.emit(this.vault, 'Transfer')
.withArgs(this.holder, ethers.ZeroAddress, 0n)
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.recipient, this.holder, 0n, 0n);
});
});
describe('inflation attack: offset price by direct deposit of assets', function () {
beforeEach(async function () {
// Donate 1 token to the vault to offset the price
await this.token.$_mint(this.vault, parseToken(1n));
});
it('status', async function () {
expect(await this.vault.totalSupply()).to.equal(0n);
expect(await this.vault.totalAssets()).to.equal(parseToken(1n));
});
/**
* | offset | deposited assets | redeemable assets |
* |--------|----------------------|----------------------|
* | 0 | 1.000000000000000000 | 0. |
* | 6 | 1.000000000000000000 | 0.999999000000000000 |
* | 18 | 1.000000000000000000 | 0.999999999999999999 |
*
* Attack is possible, but made difficult by the offset. For the attack to be successful
* the attacker needs to frontrun a deposit 10**offset times bigger than what the victim
* was trying to deposit
*/
it('deposit', async function () {
const effectiveAssets = (await this.vault.totalAssets()) + virtualAssets;
const effectiveShares = (await this.vault.totalSupply()) + virtualShares;
const depositAssets = parseToken(1n);
const expectedShares = (depositAssets * effectiveShares) / effectiveAssets;
expect(await this.vault.maxDeposit(this.holder)).to.equal(ethers.MaxUint256);
expect(await this.vault.previewDeposit(depositAssets)).to.equal(expectedShares);
const tx = this.vault.connect(this.holder).deposit(depositAssets, this.recipient);
await expect(tx).to.changeTokenBalances(
this.token,
[this.holder, this.vault],
[-depositAssets, depositAssets],
);
await expect(tx).to.changeTokenBalance(this.vault, this.recipient, expectedShares);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.holder, this.vault, depositAssets)
.to.emit(this.vault, 'Transfer')
.withArgs(ethers.ZeroAddress, this.recipient, expectedShares)
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.recipient, depositAssets, expectedShares);
});
/**
* | offset | deposited assets | redeemable assets |
* |--------|----------------------|----------------------|
* | 0 | 1000000000000000001. | 1000000000000000001. |
* | 6 | 1000000000000000001. | 1000000000000000001. |
* | 18 | 1000000000000000001. | 1000000000000000001. |
*
* Using mint protects against inflation attack, but makes minting shares very expensive.
* The ER20 allowance for the underlying asset is needed to protect the user from (too)
* large deposits.
*/
it('mint', async function () {
const effectiveAssets = (await this.vault.totalAssets()) + virtualAssets;
const effectiveShares = (await this.vault.totalSupply()) + virtualShares;
const mintShares = parseShare(1n);
const expectedAssets = (mintShares * effectiveAssets) / effectiveShares;
expect(await this.vault.maxMint(this.holder)).to.equal(ethers.MaxUint256);
expect(await this.vault.previewMint(mintShares)).to.equal(expectedAssets);
const tx = this.vault.connect(this.holder).mint(mintShares, this.recipient);
await expect(tx).to.changeTokenBalances(
this.token,
[this.holder, this.vault],
[-expectedAssets, expectedAssets],
);
await expect(tx).to.changeTokenBalance(this.vault, this.recipient, mintShares);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.holder, this.vault, expectedAssets)
.to.emit(this.vault, 'Transfer')
.withArgs(ethers.ZeroAddress, this.recipient, mintShares)
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.recipient, expectedAssets, mintShares);
});
it('withdraw', async function () {
expect(await this.vault.maxWithdraw(this.holder)).to.equal(0n);
expect(await this.vault.previewWithdraw(0n)).to.equal(0n);
const tx = this.vault.connect(this.holder).withdraw(0n, this.recipient, this.holder);
await expect(tx).to.changeTokenBalances(this.token, [this.vault, this.recipient], [0n, 0n]);
await expect(tx).to.changeTokenBalance(this.vault, this.holder, 0n);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.recipient, 0n)
.to.emit(this.vault, 'Transfer')
.withArgs(this.holder, ethers.ZeroAddress, 0n)
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.recipient, this.holder, 0n, 0n);
});
it('redeem', async function () {
expect(await this.vault.maxRedeem(this.holder)).to.equal(0n);
expect(await this.vault.previewRedeem(0n)).to.equal(0n);
const tx = this.vault.connect(this.holder).redeem(0n, this.recipient, this.holder);
await expect(tx).to.changeTokenBalances(this.token, [this.vault, this.recipient], [0n, 0n]);
await expect(tx).to.changeTokenBalance(this.vault, this.holder, 0n);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.recipient, 0n)
.to.emit(this.vault, 'Transfer')
.withArgs(this.holder, ethers.ZeroAddress, 0n)
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.recipient, this.holder, 0n, 0n);
});
});
describe('full vault: assets & shares', function () {
beforeEach(async function () {
// Add 1 token of underlying asset and 100 shares to the vault
await this.token.$_mint(this.vault, parseToken(1n));
await this.vault.$_mint(this.holder, parseShare(100n));
});
it('status', async function () {
expect(await this.vault.totalSupply()).to.equal(parseShare(100n));
expect(await this.vault.totalAssets()).to.equal(parseToken(1n));
});
/**
* | offset | deposited assets | redeemable assets |
* |--------|--------------------- |----------------------|
* | 0 | 1.000000000000000000 | 0.999999999999999999 |
* | 6 | 1.000000000000000000 | 0.999999999999999999 |
* | 18 | 1.000000000000000000 | 0.999999999999999999 |
*
* Virtual shares & assets captures part of the value
*/
it('deposit', async function () {
const effectiveAssets = (await this.vault.totalAssets()) + virtualAssets;
const effectiveShares = (await this.vault.totalSupply()) + virtualShares;
const depositAssets = parseToken(1n);
const expectedShares = (depositAssets * effectiveShares) / effectiveAssets;
expect(await this.vault.maxDeposit(this.holder)).to.equal(ethers.MaxUint256);
expect(await this.vault.previewDeposit(depositAssets)).to.equal(expectedShares);
const tx = this.vault.connect(this.holder).deposit(depositAssets, this.recipient);
await expect(tx).to.changeTokenBalances(
this.token,
[this.holder, this.vault],
[-depositAssets, depositAssets],
);
await expect(tx).to.changeTokenBalance(this.vault, this.recipient, expectedShares);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.holder, this.vault, depositAssets)
.to.emit(this.vault, 'Transfer')
.withArgs(ethers.ZeroAddress, this.recipient, expectedShares)
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.recipient, depositAssets, expectedShares);
});
/**
* | offset | deposited assets | redeemable assets |
* |--------|--------------------- |----------------------|
* | 0 | 0.010000000000000001 | 0.010000000000000000 |
* | 6 | 0.010000000000000001 | 0.010000000000000000 |
* | 18 | 0.010000000000000001 | 0.010000000000000000 |
*
* Virtual shares & assets captures part of the value
*/
it('mint', async function () {
const effectiveAssets = (await this.vault.totalAssets()) + virtualAssets;
const effectiveShares = (await this.vault.totalSupply()) + virtualShares;
const mintShares = parseShare(1n);
const expectedAssets = (mintShares * effectiveAssets) / effectiveShares + 1n; // add for the rounding
expect(await this.vault.maxMint(this.holder)).to.equal(ethers.MaxUint256);
expect(await this.vault.previewMint(mintShares)).to.equal(expectedAssets);
const tx = this.vault.connect(this.holder).mint(mintShares, this.recipient);
await expect(tx).to.changeTokenBalances(
this.token,
[this.holder, this.vault],
[-expectedAssets, expectedAssets],
);
await expect(tx).to.changeTokenBalance(this.vault, this.recipient, mintShares);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.holder, this.vault, expectedAssets)
.to.emit(this.vault, 'Transfer')
.withArgs(ethers.ZeroAddress, this.recipient, mintShares)
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.recipient, expectedAssets, mintShares);
});
it('withdraw', async function () {
const effectiveAssets = (await this.vault.totalAssets()) + virtualAssets;
const effectiveShares = (await this.vault.totalSupply()) + virtualShares;
const withdrawAssets = parseToken(1n);
const expectedShares = (withdrawAssets * effectiveShares) / effectiveAssets + 1n; // add for the rounding
expect(await this.vault.maxWithdraw(this.holder)).to.equal(withdrawAssets);
expect(await this.vault.previewWithdraw(withdrawAssets)).to.equal(expectedShares);
const tx = this.vault.connect(this.holder).withdraw(withdrawAssets, this.recipient, this.holder);
await expect(tx).to.changeTokenBalances(
this.token,
[this.vault, this.recipient],
[-withdrawAssets, withdrawAssets],
);
await expect(tx).to.changeTokenBalance(this.vault, this.holder, -expectedShares);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.recipient, withdrawAssets)
.to.emit(this.vault, 'Transfer')
.withArgs(this.holder, ethers.ZeroAddress, expectedShares)
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.recipient, this.holder, withdrawAssets, expectedShares);
});
it('withdraw with approval', async function () {
const assets = await this.vault.previewWithdraw(parseToken(1n));
await expect(this.vault.connect(this.other).withdraw(parseToken(1n), this.recipient, this.holder))
.to.be.revertedWithCustomError(this.vault, 'ERC20InsufficientAllowance')
.withArgs(this.other, 0n, assets);
await expect(this.vault.connect(this.spender).withdraw(parseToken(1n), this.recipient, this.holder)).to.not.be
.reverted;
});
it('redeem', async function () {
const effectiveAssets = (await this.vault.totalAssets()) + virtualAssets;
const effectiveShares = (await this.vault.totalSupply()) + virtualShares;
const redeemShares = parseShare(100n);
const expectedAssets = (redeemShares * effectiveAssets) / effectiveShares;
expect(await this.vault.maxRedeem(this.holder)).to.equal(redeemShares);
expect(await this.vault.previewRedeem(redeemShares)).to.equal(expectedAssets);
const tx = this.vault.connect(this.holder).redeem(redeemShares, this.recipient, this.holder);
await expect(tx).to.changeTokenBalances(
this.token,
[this.vault, this.recipient],
[-expectedAssets, expectedAssets],
);
await expect(tx).to.changeTokenBalance(this.vault, this.holder, -redeemShares);
await expect(tx)
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.recipient, expectedAssets)
.to.emit(this.vault, 'Transfer')
.withArgs(this.holder, ethers.ZeroAddress, redeemShares)
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.recipient, this.holder, expectedAssets, redeemShares);
});
it('redeem with approval', async function () {
await expect(this.vault.connect(this.other).redeem(parseShare(100n), this.recipient, this.holder))
.to.be.revertedWithCustomError(this.vault, 'ERC20InsufficientAllowance')
.withArgs(this.other, 0n, parseShare(100n));
await expect(this.vault.connect(this.spender).redeem(parseShare(100n), this.recipient, this.holder)).to.not.be
.reverted;
});
});
});
}
describe('ERC4626Fees', function () {
const feeBasisPoints = 500n; // 5%
const valueWithoutFees = 10_000n;
const fees = (valueWithoutFees * feeBasisPoints) / 10_000n;
const valueWithFees = valueWithoutFees + fees;
describe('input fees', function () {
beforeEach(async function () {
const token = await ethers.deployContract('$ERC20DecimalsMock', [name, symbol, 18n]);
const vault = await ethers.deployContract('$ERC4626FeesMock', [
'',
'',
token,
feeBasisPoints,
this.other,
0n,
ethers.ZeroAddress,
]);
await token.$_mint(this.holder, ethers.MaxUint256 / 2n);
await token.$_approve(this.holder, vault, ethers.MaxUint256 / 2n);
Object.assign(this, { token, vault });
});
it('deposit', async function () {
expect(await this.vault.previewDeposit(valueWithFees)).to.equal(valueWithoutFees);
this.tx = this.vault.connect(this.holder).deposit(valueWithFees, this.recipient);
});
it('mint', async function () {
expect(await this.vault.previewMint(valueWithoutFees)).to.equal(valueWithFees);
this.tx = this.vault.connect(this.holder).mint(valueWithoutFees, this.recipient);
});
afterEach(async function () {
await expect(this.tx).to.changeTokenBalances(
this.token,
[this.holder, this.vault, this.other],
[-valueWithFees, valueWithoutFees, fees],
);
await expect(this.tx).to.changeTokenBalance(this.vault, this.recipient, valueWithoutFees);
await expect(this.tx)
// get total
.to.emit(this.token, 'Transfer')
.withArgs(this.holder, this.vault, valueWithFees)
// redirect fees
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.other, fees)
// mint shares
.to.emit(this.vault, 'Transfer')
.withArgs(ethers.ZeroAddress, this.recipient, valueWithoutFees)
// deposit event
.to.emit(this.vault, 'Deposit')
.withArgs(this.holder, this.recipient, valueWithFees, valueWithoutFees);
});
});
describe('output fees', function () {
beforeEach(async function () {
const token = await ethers.deployContract('$ERC20DecimalsMock', [name, symbol, 18n]);
const vault = await ethers.deployContract('$ERC4626FeesMock', [
'',
'',
token,
0n,
ethers.ZeroAddress,
feeBasisPoints,
this.other,
]);
await token.$_mint(vault, ethers.MaxUint256 / 2n);
await vault.$_mint(this.holder, ethers.MaxUint256 / 2n);
Object.assign(this, { token, vault });
});
it('redeem', async function () {
expect(await this.vault.previewRedeem(valueWithFees)).to.equal(valueWithoutFees);
this.tx = this.vault.connect(this.holder).redeem(valueWithFees, this.recipient, this.holder);
});
it('withdraw', async function () {
expect(await this.vault.previewWithdraw(valueWithoutFees)).to.equal(valueWithFees);
this.tx = this.vault.connect(this.holder).withdraw(valueWithoutFees, this.recipient, this.holder);
});
afterEach(async function () {
await expect(this.tx).to.changeTokenBalances(
this.token,
[this.vault, this.recipient, this.other],
[-valueWithFees, valueWithoutFees, fees],
);
await expect(this.tx).to.changeTokenBalance(this.vault, this.holder, -valueWithFees);
await expect(this.tx)
// withdraw principal
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.recipient, valueWithoutFees)
// redirect fees
.to.emit(this.token, 'Transfer')
.withArgs(this.vault, this.other, fees)
// mint shares
.to.emit(this.vault, 'Transfer')
.withArgs(this.holder, ethers.ZeroAddress, valueWithFees)
// withdraw event
.to.emit(this.vault, 'Withdraw')
.withArgs(this.holder, this.recipient, this.holder, valueWithoutFees, valueWithFees);
});
});
});
/// Scenario inspired by solmate ERC4626 tests:
/// https://github.com/transmissions11/solmate/blob/main/src/test/ERC4626.t.sol
it('multiple mint, deposit, redeem & withdrawal', async function () {
// test designed with both asset using similar decimals
const [alice, bruce] = this.accounts;
const token = await ethers.deployContract('$ERC20DecimalsMock', [name, symbol, 18n]);
const vault = await ethers.deployContract('$ERC4626', ['', '', token]);
await token.$_mint(alice, 4000n);
await token.$_mint(bruce, 7001n);
await token.connect(alice).approve(vault, 4000n);
await token.connect(bruce).approve(vault, 7001n);
// 1. Alice mints 2000 shares (costs 2000 tokens)
await expect(vault.connect(alice).mint(2000n, alice))
.to.emit(token, 'Transfer')
.withArgs(alice, vault, 2000n)
.to.emit(vault, 'Transfer')
.withArgs(ethers.ZeroAddress, alice, 2000n);
expect(await vault.previewDeposit(2000n)).to.equal(2000n);
expect(await vault.balanceOf(alice)).to.equal(2000n);
expect(await vault.balanceOf(bruce)).to.equal(0n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(2000n);
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(0n);
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(2000n);
expect(await vault.totalSupply()).to.equal(2000n);
expect(await vault.totalAssets()).to.equal(2000n);
// 2. Bruce deposits 4000 tokens (mints 4000 shares)
await expect(vault.connect(bruce).mint(4000n, bruce))
.to.emit(token, 'Transfer')
.withArgs(bruce, vault, 4000n)
.to.emit(vault, 'Transfer')
.withArgs(ethers.ZeroAddress, bruce, 4000n);
expect(await vault.previewDeposit(4000n)).to.equal(4000n);
expect(await vault.balanceOf(alice)).to.equal(2000n);
expect(await vault.balanceOf(bruce)).to.equal(4000n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(2000n);
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(4000n);
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(6000n);
expect(await vault.totalSupply()).to.equal(6000n);
expect(await vault.totalAssets()).to.equal(6000n);
// 3. Vault mutates by +3000 tokens (simulated yield returned from strategy)
await token.$_mint(vault, 3000n);
expect(await vault.balanceOf(alice)).to.equal(2000n);
expect(await vault.balanceOf(bruce)).to.equal(4000n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(2999n); // used to be 3000, but virtual assets/shares captures part of the yield
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(5999n); // used to be 6000, but virtual assets/shares captures part of the yield
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(6000n);
expect(await vault.totalSupply()).to.equal(6000n);
expect(await vault.totalAssets()).to.equal(9000n);
// 4. Alice deposits 2000 tokens (mints 1333 shares)
await expect(vault.connect(alice).deposit(2000n, alice))
.to.emit(token, 'Transfer')
.withArgs(alice, vault, 2000n)
.to.emit(vault, 'Transfer')
.withArgs(ethers.ZeroAddress, alice, 1333n);
expect(await vault.balanceOf(alice)).to.equal(3333n);
expect(await vault.balanceOf(bruce)).to.equal(4000n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(4999n);
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(6000n);
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(7333n);
expect(await vault.totalSupply()).to.equal(7333n);
expect(await vault.totalAssets()).to.equal(11000n);
// 5. Bruce mints 2000 shares (costs 3001 assets)
// NOTE: Bruce's assets spent got rounded towards infinity
// NOTE: Alices's vault assets got rounded towards infinity
await expect(vault.connect(bruce).mint(2000n, bruce))
.to.emit(token, 'Transfer')
.withArgs(bruce, vault, 3000n)
.to.emit(vault, 'Transfer')
.withArgs(ethers.ZeroAddress, bruce, 2000n);
expect(await vault.balanceOf(alice)).to.equal(3333n);
expect(await vault.balanceOf(bruce)).to.equal(6000n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(4999n); // used to be 5000
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(9000n);
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(9333n);
expect(await vault.totalSupply()).to.equal(9333n);
expect(await vault.totalAssets()).to.equal(14000n); // used to be 14001
// 6. Vault mutates by +3000 tokens
// NOTE: Vault holds 17001 tokens, but sum of assetsOf() is 17000.
await token.$_mint(vault, 3000n);
expect(await vault.balanceOf(alice)).to.equal(3333n);
expect(await vault.balanceOf(bruce)).to.equal(6000n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(6070n); // used to be 6071
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(10928n); // used to be 10929
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(9333n);
expect(await vault.totalSupply()).to.equal(9333n);
expect(await vault.totalAssets()).to.equal(17000n); // used to be 17001
// 7. Alice redeem 1333 shares (2428 assets)
await expect(vault.connect(alice).redeem(1333n, alice, alice))
.to.emit(vault, 'Transfer')
.withArgs(alice, ethers.ZeroAddress, 1333n)
.to.emit(token, 'Transfer')
.withArgs(vault, alice, 2427n); // used to be 2428
expect(await vault.balanceOf(alice)).to.equal(2000n);
expect(await vault.balanceOf(bruce)).to.equal(6000n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(3643n);
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(10929n);
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(8000n);
expect(await vault.totalSupply()).to.equal(8000n);
expect(await vault.totalAssets()).to.equal(14573n);
// 8. Bruce withdraws 2929 assets (1608 shares)
await expect(vault.connect(bruce).withdraw(2929n, bruce, bruce))
.to.emit(vault, 'Transfer')
.withArgs(bruce, ethers.ZeroAddress, 1608n)
.to.emit(token, 'Transfer')
.withArgs(vault, bruce, 2929n);
expect(await vault.balanceOf(alice)).to.equal(2000n);
expect(await vault.balanceOf(bruce)).to.equal(4392n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(3643n);
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(8000n);
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(6392n);
expect(await vault.totalSupply()).to.equal(6392n);
expect(await vault.totalAssets()).to.equal(11644n);
// 9. Alice withdraws 3643 assets (2000 shares)
// NOTE: Bruce's assets have been rounded back towards infinity
await expect(vault.connect(alice).withdraw(3643n, alice, alice))
.to.emit(vault, 'Transfer')
.withArgs(alice, ethers.ZeroAddress, 2000n)
.to.emit(token, 'Transfer')
.withArgs(vault, alice, 3643n);
expect(await vault.balanceOf(alice)).to.equal(0n);
expect(await vault.balanceOf(bruce)).to.equal(4392n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(0n);
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(8000n); // used to be 8001
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(4392n);
expect(await vault.totalSupply()).to.equal(4392n);
expect(await vault.totalAssets()).to.equal(8001n);
// 10. Bruce redeem 4392 shares (8001 tokens)
await expect(vault.connect(bruce).redeem(4392n, bruce, bruce))
.to.emit(vault, 'Transfer')
.withArgs(bruce, ethers.ZeroAddress, 4392n)
.to.emit(token, 'Transfer')
.withArgs(vault, bruce, 8000n); // used to be 8001
expect(await vault.balanceOf(alice)).to.equal(0n);
expect(await vault.balanceOf(bruce)).to.equal(0n);
expect(await vault.convertToAssets(await vault.balanceOf(alice))).to.equal(0n);
expect(await vault.convertToAssets(await vault.balanceOf(bruce))).to.equal(0n);
expect(await vault.convertToShares(await token.balanceOf(vault))).to.equal(0n);
expect(await vault.totalSupply()).to.equal(0n);
expect(await vault.totalAssets()).to.equal(1n); // used to be 0
});
});