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| 1 | +import { BigNumber, BigNumberish, Wallet, utils, providers } from 'ethers' |
| 2 | +import { AddressZero } from '@ethersproject/constants' |
| 3 | +import { expect, use } from 'chai' |
| 4 | +import { waffle, network } from 'hardhat' |
| 5 | + |
| 6 | +import { timeTravel } from 'utils/timeTravel' |
| 7 | +import { |
| 8 | + MockV3Aggregator, |
| 9 | + MockV3Aggregator__factory, |
| 10 | + TrueCurrencyWithPoR, |
| 11 | + TrueUSDWithPoR__factory, |
| 12 | +} from 'contracts' |
| 13 | + |
| 14 | +use(waffle.solidity) |
| 15 | + |
| 16 | +// = base * 10^{exponent} |
| 17 | +const exp = (base: BigNumberish, exponent: BigNumberish): BigNumber => { |
| 18 | + return BigNumber.from(base).mul(BigNumber.from(10).pow(exponent)) |
| 19 | +} |
| 20 | + |
| 21 | +describe('TrueCurrency with Proof-of-reserves check', () => { |
| 22 | + const ONE_DAY_SECONDS = 24 * 60 * 60 // seconds in a day |
| 23 | + const TUSD_FEED_INITIAL_ANSWER = exp(1_000_000, 18).toString() // "1M TUSD in reserves" |
| 24 | + const AMOUNT_TO_MINT = utils.parseEther('1000000') |
| 25 | + let token: TrueCurrencyWithPoR |
| 26 | + let mockV3Aggregator: MockV3Aggregator |
| 27 | + let owner: Wallet |
| 28 | + |
| 29 | + before(async () => { |
| 30 | + const provider = waffle.provider; |
| 31 | + [owner] = provider.getWallets() |
| 32 | + |
| 33 | + token = (await new TrueUSDWithPoR__factory(owner).deploy()) as TrueCurrencyWithPoR |
| 34 | + |
| 35 | + // Deploy a mock aggregator to mock Proof of Reserve feed answers |
| 36 | + mockV3Aggregator = await new MockV3Aggregator__factory(owner).deploy( |
| 37 | + '18', |
| 38 | + TUSD_FEED_INITIAL_ANSWER, |
| 39 | + ) |
| 40 | + }) |
| 41 | + |
| 42 | + beforeEach(async () => { |
| 43 | + // Reset pool Proof Of Reserve feed defaults |
| 44 | + const currentFeed = await token.chainReserveFeed() |
| 45 | + if (currentFeed.toLowerCase() !== mockV3Aggregator.address.toLowerCase()) { |
| 46 | + await token.setChainReserveFeed(mockV3Aggregator.address) |
| 47 | + await token.setChainReserveHeartbeat(ONE_DAY_SECONDS) |
| 48 | + await token.enableProofOfReserve() |
| 49 | + } |
| 50 | + |
| 51 | + // Set fresh, valid answer on mock Proof of Reserve feed |
| 52 | + const tusdSupply = await token.totalSupply() |
| 53 | + await mockV3Aggregator.updateAnswer(tusdSupply.add(AMOUNT_TO_MINT)) |
| 54 | + }) |
| 55 | + |
| 56 | + it('should mint successfully when feed is unset', async () => { |
| 57 | + // Make sure feed is unset |
| 58 | + await token.setChainReserveFeed(AddressZero) |
| 59 | + expect(await token.chainReserveFeed()).to.equal(AddressZero) |
| 60 | + |
| 61 | + // Mint TUSD |
| 62 | + const balanceBefore = await token.balanceOf(owner.address) |
| 63 | + await token.mint(owner.address, AMOUNT_TO_MINT) |
| 64 | + expect(await token.balanceOf(owner.address)).to.equal(balanceBefore.add(AMOUNT_TO_MINT)) |
| 65 | + }) |
| 66 | + |
| 67 | + it('should mint successfully when feed is set, but heartbeat is default', async () => { |
| 68 | + // Mint TUSD |
| 69 | + const balanceBefore = await token.balanceOf(owner.address) |
| 70 | + await token.mint(owner.address, AMOUNT_TO_MINT) |
| 71 | + expect(await token.balanceOf(owner.address)).to.equal(AMOUNT_TO_MINT.add(balanceBefore)) |
| 72 | + }) |
| 73 | + |
| 74 | + it('should mint successfully when both feed and heartbeat are set', async () => { |
| 75 | + // Set heartbeat to 1 day |
| 76 | + await token.setChainReserveHeartbeat(ONE_DAY_SECONDS) |
| 77 | + expect(await token.chainReserveHeartbeat()).to.equal(ONE_DAY_SECONDS) |
| 78 | + |
| 79 | + // Mint TUSD |
| 80 | + const balanceBefore = await token.balanceOf(owner.address) |
| 81 | + await token.mint(owner.address, AMOUNT_TO_MINT) |
| 82 | + expect(await token.balanceOf(owner.address)).to.equal(balanceBefore.add(AMOUNT_TO_MINT)) |
| 83 | + }) |
| 84 | + |
| 85 | + it('should revert mint when feed decimals < TrueCurrency decimals', async () => { |
| 86 | + const currentTusdSupply = await token.totalSupply() |
| 87 | + const validReserve = currentTusdSupply.div(exp(1, 12)).add(AMOUNT_TO_MINT) |
| 88 | + |
| 89 | + // Re-deploy a mock aggregator with fewer decimals |
| 90 | + const mockV3AggregatorWith6Decimals = await new MockV3Aggregator__factory(owner).deploy('6', validReserve) |
| 91 | + // Set feed and heartbeat on newly-deployed aggregator |
| 92 | + await token.setChainReserveFeed(mockV3AggregatorWith6Decimals.address) |
| 93 | + await token.setChainReserveHeartbeat(ONE_DAY_SECONDS) |
| 94 | + await token.enableProofOfReserve() |
| 95 | + expect(await token.chainReserveFeed()).to.equal(mockV3AggregatorWith6Decimals.address) |
| 96 | + |
| 97 | + // Mint TUSD |
| 98 | + const balanceBefore = await token.balanceOf(owner.address) |
| 99 | + await expect(token.mint(owner.address, AMOUNT_TO_MINT)).to.be.revertedWith('TrueCurrency: Unexpected decimals of PoR feed') |
| 100 | + expect(await token.balanceOf(owner.address)).to.equal(balanceBefore) |
| 101 | + }) |
| 102 | + |
| 103 | + it('should revert mint when feed decimals > TrueCurrency decimals', async () => { |
| 104 | + // Re-deploy a mock aggregator with more decimals |
| 105 | + const currentTusdSupply = await token.totalSupply() |
| 106 | + const validReserve = currentTusdSupply.div(exp(1, 12)).add(AMOUNT_TO_MINT) |
| 107 | + |
| 108 | + const mockV3AggregatorWith20Decimals = await new MockV3Aggregator__factory(owner).deploy('20', validReserve) |
| 109 | + // Set feed and heartbeat on newly-deployed aggregator |
| 110 | + await token.setChainReserveFeed(mockV3AggregatorWith20Decimals.address) |
| 111 | + await token.setChainReserveHeartbeat(ONE_DAY_SECONDS) |
| 112 | + await token.enableProofOfReserve() |
| 113 | + expect(await token.chainReserveFeed()).to.equal(mockV3AggregatorWith20Decimals.address) |
| 114 | + |
| 115 | + // Mint TUSD |
| 116 | + const balanceBefore = await token.balanceOf(owner.address) |
| 117 | + await expect(token.mint(owner.address, AMOUNT_TO_MINT)).to.be.revertedWith('TrueCurrency: Unexpected decimals of PoR feed') |
| 118 | + expect(await token.balanceOf(owner.address)).to.equal(balanceBefore) |
| 119 | + }) |
| 120 | + |
| 121 | + it('should mint successfully when TrueCurrency supply == proof-of-reserves', async () => { |
| 122 | + // Mint TUSD |
| 123 | + const balanceBefore = await token.balanceOf(owner.address) |
| 124 | + await token.mint(owner.address, AMOUNT_TO_MINT) |
| 125 | + expect(await token.balanceOf(owner.address)).to.equal(balanceBefore.add(AMOUNT_TO_MINT)) |
| 126 | + }) |
| 127 | + |
| 128 | + it('should revert if TrueCurrency supply > proof-of-reserves', async () => { |
| 129 | + const currentTusdSupply = await token.totalSupply() |
| 130 | + const notEnoughReserves = currentTusdSupply.sub('1') |
| 131 | + await mockV3Aggregator.updateAnswer(notEnoughReserves) |
| 132 | + |
| 133 | + // Mint TUSD |
| 134 | + const balanceBefore = await token.balanceOf(owner.address) |
| 135 | + await expect(token.mint(owner.address, AMOUNT_TO_MINT)).to.be.revertedWith( |
| 136 | + 'TrueCurrency: total supply would exceed reserves after mint', |
| 137 | + ) |
| 138 | + expect(await token.balanceOf(owner.address)).to.equal(balanceBefore) |
| 139 | + }) |
| 140 | + |
| 141 | + it('should revert if the feed is not updated within the heartbeat', async () => { |
| 142 | + // Set heartbeat to 1 day |
| 143 | + await token.setChainReserveHeartbeat(ONE_DAY_SECONDS) |
| 144 | + await token.enableProofOfReserve() |
| 145 | + expect(await token.chainReserveHeartbeat()).to.equal(ONE_DAY_SECONDS) |
| 146 | + |
| 147 | + // Heartbeat is set to 1 day, so fast-forward 2 days |
| 148 | + await timeTravel(<unknown> network.provider as providers.JsonRpcProvider, 2 * ONE_DAY_SECONDS) |
| 149 | + |
| 150 | + // Mint TUSD |
| 151 | + const balanceBefore = await token.balanceOf(owner.address) |
| 152 | + await expect(token.mint(owner.address, AMOUNT_TO_MINT)).to.be.revertedWith('TrueCurrency: PoR answer too old') |
| 153 | + expect(await token.balanceOf(owner.address)).to.equal(balanceBefore) |
| 154 | + }) |
| 155 | + |
| 156 | + it('should revert if feed returns an invalid answer', async () => { |
| 157 | + // Update feed with invalid answer |
| 158 | + await mockV3Aggregator.updateAnswer(0) |
| 159 | + |
| 160 | + // Mint TUSD |
| 161 | + const balanceBefore = await token.balanceOf(owner.address) |
| 162 | + await expect(token.mint(owner.address, AMOUNT_TO_MINT)).to.be.revertedWith('TrueCurrency: Invalid answer from PoR feed') |
| 163 | + expect(await token.balanceOf(owner.address)).to.equal(balanceBefore) |
| 164 | + }) |
| 165 | + |
| 166 | + it('should emit NewChainReserveHeartbeatChanged if setChainReserveHeartbeat called successfully', async () => { |
| 167 | + const oldChainReserveHeartbeat = await token.chainReserveHeartbeat() |
| 168 | + await expect(token.setChainReserveHeartbeat(2 * ONE_DAY_SECONDS)) |
| 169 | + .to.emit(token, 'NewChainReserveHeartbeat').withArgs(oldChainReserveHeartbeat, 2 * ONE_DAY_SECONDS) |
| 170 | + }) |
| 171 | + |
| 172 | + it('should emit NewChainReserveFeed if setChainReserveFeed called successfully', async () => { |
| 173 | + const oldChainReserveFeed = await token.chainReserveFeed() |
| 174 | + await expect(token.setChainReserveFeed(AddressZero)) |
| 175 | + .to.emit(token, 'NewChainReserveFeed').withArgs(oldChainReserveFeed, AddressZero) |
| 176 | + }) |
| 177 | +}) |
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