Merge pull request #178 from keep-network/update-hardhat

Update hardhat version and fix unit tests

Due to an error in Hardhat 2.2.0 (NomicFoundation/hardhat#1415)
we decided to update Hardhat version and fix errors in unit and system tests.

The errors in tests were caused by functions like isOpen, takeOffer, earlyClose
being called on auctions that self destructed (the previously used version of Hardhat
seemed to tolerate such calls).

package.json

@@ -45,7 +45,7 @@
     "eslint-config-keep": "github:keep-network/eslint-config-keep#0c27ade",
     "ethereum-waffle": "^3.3.0",
     "ethers": "^5.0.32",
-    "hardhat": "^2.1.1",
+    "hardhat": "^2.6.1",
     "hardhat-deploy": "^0.8.11",
     "hardhat-gas-reporter": "^1.0.4",
     "prettier": "^2.3.2",

test/Auction.test.js

@@ -7,6 +7,7 @@ const {
   pastEvents,
   increaseTime,
   impersonateAccount,
+  isCodeAt,
 } = require("./helpers/contract-test-helpers")
 
 const { BigNumber } = ethers
@@ -150,6 +151,9 @@ describe("Auction", () => {
         // add 100sec
         await increaseTime(100)
 
+        // make sure auction did not self destruct
+        expect(await isCodeAt(auction.address)).to.be.true
+
         expect(await auction.isOpen()).to.be.equal(true)
       })
     })
@@ -164,6 +168,7 @@ describe("Auction", () => {
       })
 
       it("should be opened", async () => {
+        expect(await isCodeAt(auction.address)).to.be.true
         expect(await auction.isOpen()).to.be.equal(true)
       })
 
@@ -275,17 +280,15 @@ describe("Auction", () => {
     })
 
     context("when the auction was fully paid off and is closed", () => {
-      it("should revert on taking offer again", async () => {
+      it("should destroy the auction", async () => {
         // Increase time 1h -> 3600sec
         await increaseTime(3600)
 
         // take the entire auction
         await auction.connect(bidder1).takeOffer(auctionAmountDesired)
 
-        // another bidder is trying to take offer on a closed auction
-        await expect(
-          auction.connect(bidder2).takeOffer(BigNumber.from(1))
-        ).to.be.revertedWith("Address: call to non-contract")
+        // the auction contract address should not store code anymore
+        expect(await isCodeAt(auction.address)).to.be.false
       })
     })
 
@@ -516,14 +519,18 @@ describe("Auction", () => {
           // Increase time so the auction ends
           // 3,600 + 82,800 + 1 = 86401sec (auction ended)
           await increaseTime(82801)
+          // when auction ends and is partially filled, it should not self
+          // destruct
+          expect(await isCodeAt(auction.address)).to.be.true
+
           // when auction ends and is partially filled, it should stay opened
           expect(await auction.isOpen()).to.be.equal(true)
         })
       }
     )
 
     context("when the auction was fully paid off in partial offers", () => {
-      it("should revert on taking another offer", async () => {
+      it("should destroy the auction", async () => {
         // Auction amount desired: 1 * 10^18
         // Increase time 1h -> 3600sec
         await increaseTime(3600)
@@ -538,9 +545,7 @@ describe("Auction", () => {
           .amountOutstanding()
         await auction.connect(bidder2).takeOffer(amountOutstanding)
 
-        await expect(
-          auction.connect(bidder2).takeOffer(BigNumber.from(1))
-        ).to.be.revertedWith("Address: call to non-contract")
+        expect(await isCodeAt(auction.address)).to.be.false
       })
     })
   })
@@ -558,21 +563,21 @@ describe("Auction", () => {
     })
 
     context("when the auction is open and there are no fills", () => {
-      it("should early close the auction", async () => {
+      it("should destroy the auction", async () => {
         await auction.connect(auctioneerSigner).earlyClose()
 
-        expect(await auction.isOpen()).to.be.false
+        expect(await isCodeAt(auction.address)).to.be.false
       })
     })
 
     context("when the auction is open and there are partial fills", () => {
-      it("should early close the auction", async () => {
+      it("should destroy the auction", async () => {
         const partialOfferAmount = auctionAmountDesired.div(BigNumber.from("2"))
         await auction.connect(bidder1).takeOffer(partialOfferAmount)
 
         await auction.connect(auctioneerSigner).earlyClose()
 
-        expect(await auction.isOpen()).to.be.false
+        expect(await isCodeAt(auction.address)).to.be.false
       })
     })
 
@@ -583,19 +588,6 @@ describe("Auction", () => {
         )
       })
     })
-
-    context("when the auction is closed", () => {
-      it("should revert", async () => {
-        // close the auction by taking the whole amount
-        await auction.connect(bidder1).takeOffer(auctionAmountDesired)
-
-        // Will be reverted due to onlyAuctioneer modifier violation as
-        // Auction storage has been destroyed by harikari and current
-        // auctioneer is a zero address.
-        await expect(auction.connect(auctioneerSigner).earlyClose()).to.be
-          .reverted
-      })
-    })
   })
 
   describe("amountTransferred", () => {

test/Auctioneer.test.js

@@ -5,6 +5,7 @@ const {
   to1e18,
   pastEvents,
   increaseTime,
+  isCodeAt,
 } = require("./helpers/contract-test-helpers")
 
 const auctionLength = 86400 // 24h in sec
@@ -264,10 +265,10 @@ describe("Auctioneer", () => {
     })
 
     context("when the auction is still open", () => {
-      it("should close the auction", async () => {
+      it("should destroy the auction", async () => {
         await auctioneer.connect(bidder).publicEarlyCloseAuction(auctionAddress)
 
-        expect(await auction.isOpen()).to.be.false
+        expect(await isCodeAt(auctionAddress)).to.be.false
       })
 
       it("should emit the auction closed event", async () => {

test/helpers/contract-test-helpers.js

@@ -78,12 +78,20 @@ async function resetFork(blockNumber) {
   })
 }
 
+// This function checks whether the given address stores contract code. It
+// can be used to determine whether a contract stored at the given address has
+// self destructed.
+async function isCodeAt(address) {
+  return (await ethers.provider.getCode(address)) != ethers.utils.hexlify("0x")
+}
+
 module.exports.to1ePrecision = to1ePrecision
 module.exports.to1e18 = to1e18
 module.exports.pastEvents = pastEvents
 module.exports.lastBlockTime = lastBlockTime
 module.exports.increaseTime = increaseTime
 module.exports.impersonateAccount = impersonateAccount
 module.exports.resetFork = resetFork
+module.exports.isCodeAt = isCodeAt
 
 module.exports.ZERO_ADDRESS = "0x0000000000000000000000000000000000000000"

test/system/liquidation-multiple-take-offers.test.js

@@ -7,6 +7,7 @@ const {
   resetFork,
   ZERO_ADDRESS,
   increaseTime,
+  isCodeAt,
 } = require("../helpers/contract-test-helpers")
 const {
   underwriterAddress,
@@ -128,8 +129,8 @@ describeFn("System -- multiple partial fills", () => {
       tx = await auction.connect(bidder2).takeOffer(lotSize.mul(60).div(100))
     })
 
-    it("should close auction", async () => {
-      expect(await auction.isOpen()).to.be.false
+    it("should destroy auction", async () => {
+      expect(await isCodeAt(auction.address)).to.be.false
     })
 
     it("should decrease the amount of TBTC for bidders", async () => {
@@ -177,7 +178,7 @@ describeFn("System -- multiple partial fills", () => {
       expect(parseInt(tx.gasLimit)).to.be.lessThan(370000)
 
       const txReceipt = await ethers.provider.getTransactionReceipt(tx.hash)
-      expect(parseInt(txReceipt.gasUsed)).to.be.lessThan(181000)
+      expect(parseInt(txReceipt.gasUsed)).to.be.lessThan(280000)
     })
   })
 })

test/system/liquidation.test.js

@@ -6,6 +6,7 @@ const {
   resetFork,
   ZERO_ADDRESS,
   increaseTime,
+  isCodeAt,
 } = require("../helpers/contract-test-helpers")
 const hre = require("hardhat")
 
@@ -135,8 +136,8 @@ describeFn("System -- liquidation", () => {
       tx = await auction.takeOffer(lotSize)
     })
 
-    it("should close auction", async () => {
-      expect(await auction.isOpen()).to.be.false
+    it("should destroy auction", async () => {
+      expect(await isCodeAt(auction.address)).to.be.false
     })
 
     it("should spend bidder's TBTC", async () => {
@@ -180,7 +181,7 @@ describeFn("System -- liquidation", () => {
       await expect(parseInt(tx.gasLimit)).to.be.lessThan(518000)
 
       const txReceipt = await ethers.provider.getTransactionReceipt(tx.hash)
-      await expect(parseInt(txReceipt.gasUsed)).to.be.lessThan(255000)
+      await expect(parseInt(txReceipt.gasUsed)).to.be.lessThan(392000)
     })
   })
 })

test/system/surplus-for-auction.test.js

@@ -6,6 +6,7 @@ const {
   resetFork,
   to1ePrecision,
   ZERO_ADDRESS,
+  isCodeAt,
 } = require("../helpers/contract-test-helpers")
 const Auction = hre.artifacts.readArtifactSync("Auction")
 const { initContracts } = require("./init-contracts")
@@ -159,7 +160,7 @@ describeFn("System -- buying a deposit with surplus", () => {
     })
 
     it("should early close cov pool auction for deposit2", async () => {
-      expect(await auction.isOpen()).to.be.false
+      expect(await isCodeAt(auction.address)).to.be.false
     })
 
     it("should buy deposit3 with surplus TBTC without opening an auction", async () => {