Add more test cases

.gitignore

@@ -11,5 +11,6 @@
 /coverage.json
 
 /temp-artifacts
+/src/contracts/hardhat-dependency-compiler
 
 .DS_Store

package.json

@@ -35,6 +35,8 @@
     "bluebird": "^3.7.2",
     "chai": "^4.3.6",
     "dotenv": "^16.0.3",
+    "eth-sig-util": "^3.0.1",
+    "ethereumjs-util": "^7.1.5",
     "ethers": "^5.6.4",
     "hardhat": "^2.9.3",
     "hardhat-contract-sizer": "^2.6.1",

src/contracts/facilitators/flashMinter/mocks/MockFlashBorrower.sol

@@ -4,7 +4,13 @@ pragma solidity ^0.8.10;
 import {IERC20} from '@openzeppelin/contracts/token/ERC20/IERC20.sol';
 import {IERC3156FlashBorrower} from '@openzeppelin/contracts/interfaces/IERC3156FlashBorrower.sol';
 import {IERC3156FlashLender} from '@openzeppelin/contracts/interfaces/IERC3156FlashLender.sol';
+import {IGhoToken} from '../../../gho/interfaces/IGhoToken.sol';
 
+/**
+ * @title MockFlashBorrower
+ * @author Aave
+ * @dev This is purely an unsafe mock testing contract. Do not use in production.
+ */
 contract MockFlashBorrower is IERC3156FlashBorrower {
   enum Action {
     NORMAL,
@@ -13,11 +19,13 @@ contract MockFlashBorrower is IERC3156FlashBorrower {
 
   IERC3156FlashLender private _lender;
 
-  bool allowRepayment;
+  bool private _allowRepayment;
+  bool private _allowCallback;
 
   constructor(IERC3156FlashLender lender) {
     _lender = lender;
-    allowRepayment = true;
+    _allowRepayment = true;
+    _allowCallback = true;
   }
 
   /// @dev ERC-3156 Flash loan callback
@@ -30,30 +38,58 @@ contract MockFlashBorrower is IERC3156FlashBorrower {
   ) external override returns (bytes32) {
     require(msg.sender == address(_lender), 'FlashBorrower: Untrusted lender');
     require(initiator == address(this), 'FlashBorrower: Untrusted loan initiator');
+
     Action action = abi.decode(data, (Action));
+
     if (action == Action.NORMAL) {
-      // do one thing
+      // Intentionally left blank.
     } else if (action == Action.OTHER) {
-      // do another
+      // Tests capacity change mid-flashmint.
+      require(
+        _lender.flashFee(token, type(uint128).max) == 0,
+        'FlashBorrower: Non-zero flashfee during capacity change test'
+      );
+
+      (uint256 capacityBefore, ) = IGhoToken(token).getFacilitatorBucket(address(_lender));
+      require(capacityBefore != 0, 'FlashBorrower: Zero bucket capacity before setting');
+
+      IGhoToken(token).setFacilitatorBucketCapacity(address(_lender), 0);
+
+      (uint256 capacityAfter, ) = IGhoToken(token).getFacilitatorBucket(address(_lender));
+      require(capacityAfter == 0, 'FlashBorrower: Non-zero bucket capacity after setting');
+
+      require(
+        _lender.maxFlashLoan(token) == 0,
+        'FlashBorrower: Non-zero max flashloan at capacity < level'
+      );
+    }
+
+    // Repayment
+    if (_allowRepayment) {
+      IERC20(token).approve(address(_lender), amount + fee);
     }
-    return keccak256('ERC3156FlashBorrower.onFlashLoan');
+    return _allowCallback ? keccak256('ERC3156FlashBorrower.onFlashLoan') : keccak256('arbitrary');
   }
 
   /// @dev Initiate a flash loan
   function flashBorrow(address token, uint256 amount) public {
     bytes memory data = abi.encode(Action.NORMAL);
 
-    if (allowRepayment) {
-      uint256 allowance = IERC20(token).allowance(address(this), address(_lender));
-      uint256 fee = _lender.flashFee(token, amount);
-      uint256 repayment = amount + fee;
-      IERC20(token).approve(address(_lender), allowance + repayment);
-    }
+    _lender.flashLoan(this, token, amount, data);
+  }
+
+  function flashBorrowOtherActionMax(address token) public {
+    bytes memory data = abi.encode(Action.OTHER);
+    uint256 amount = _lender.maxFlashLoan(token);
 
     _lender.flashLoan(this, token, amount, data);
   }
 
   function setAllowRepayment(bool active) public {
-    allowRepayment = active;
+    _allowRepayment = active;
+  }
+
+  function setAllowCallback(bool active) public {
+    _allowCallback = active;
   }
 }

src/helpers/types.ts

@@ -1 +1,2 @@
 export type tEthereumAddress = string;
+export type tStringTokenSmallUnits = string; // 1 wei, or 1 basic unit of USDC, or 1 basic unit of DAI

src/test/basic-borrow.test.ts

@@ -1,3 +1,4 @@
+import hre from 'hardhat';
 import { expect } from 'chai';
 import { BigNumber } from 'ethers';
 import './helpers/math/wadraymath';
@@ -37,14 +38,15 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
       .connect(users[0].signer)
       .borrow(gho.address, borrowAmount, 2, 0, users[0].address);
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(ZERO_ADDRESS, users[0].address, borrowAmount)
       .to.emit(variableDebtToken, 'Mint')
       .withArgs(users[0].address, users[0].address, borrowAmount, 0, oneRay)
       .to.not.emit(variableDebtToken, 'DiscountPercentLocked');
 
     expect(await gho.balanceOf(users[0].address)).to.be.equal(borrowAmount);
+    expect(await variableDebtToken.totalSupply()).to.be.equal(borrowAmount);
     expect(await variableDebtToken.getBalanceFromInterest(users[0].address)).to.be.equal(0);
     expect(await variableDebtToken.balanceOf(users[0].address)).to.be.equal(borrowAmount);
   });
@@ -74,6 +76,7 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
 
     expect(await gho.balanceOf(users[0].address)).to.be.equal(borrowAmount);
     expect(user1Year1Debt).to.be.eq(user1ExpectedBalance);
+    expect(await variableDebtToken.totalSupply()).to.be.equal(user1ExpectedBalance);
     expect(await variableDebtToken.getBalanceFromInterest(users[0].address)).to.be.equal(0);
   });
 
@@ -100,7 +103,7 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
     );
     const expIndex = variableBorrowIndex.rayMul(multiplier);
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(ZERO_ADDRESS, users[1].address, borrowAmount)
       .to.emit(variableDebtToken, 'Mint')
@@ -144,7 +147,7 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
     const amount = user1ExpectedBalance.sub(borrowAmount);
     const user1ExpectedBalanceIncrease = amount.sub(borrowAmount);
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(ZERO_ADDRESS, users[0].address, amount)
       .to.emit(variableDebtToken, 'Mint')
@@ -192,7 +195,7 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
     const user2ExpectedBalance = user2ScaledBefore.rayMul(expIndex);
     const user2ExpectedInterest = user2ExpectedBalance.sub(borrowAmount);
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(users[1].address, ZERO_ADDRESS, borrowAmount)
       .to.emit(variableDebtToken, 'Burn')
@@ -237,7 +240,7 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
     );
     const expIndex = variableBorrowIndex.rayMul(multiplier);
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(ZERO_ADDRESS, users[2].address, borrowAmount.mul(3))
       .to.emit(variableDebtToken, 'Mint')
@@ -281,7 +284,7 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
     const expectedATokenGhoBalance = aTokenGhoBalanceBefore.add(repayAmount);
 
     const amount = user1ExpectedBalanceIncrease.sub(repayAmount);
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(ZERO_ADDRESS, users[0].address, amount)
       .to.emit(variableDebtToken, 'Mint')
@@ -330,7 +333,7 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
     const expectedATokenGhoBalance = aTokenGhoBalanceBefore.add(user1ExpectedInterest);
 
     const amount = user1ExpectedBalance.sub(user1ExpectedBalanceIncrease);
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(users[0].address, ZERO_ADDRESS, amount)
       .to.emit(variableDebtToken, 'Burn')
@@ -353,7 +356,7 @@ makeSuite('Gho Basic Borrow Flow', (testEnv: TestEnv) => {
 
     const tx = await aToken.distributeFeesToTreasury();
 
-    expect(tx)
+    await expect(tx)
       .to.emit(aToken, 'FeesDistributedToTreasury')
       .withArgs(treasuryAddress, gho.address, aTokenBalance);
 

src/test/borrow-onBehalf.test.ts

@@ -1,3 +1,4 @@
+import hre from 'hardhat';
 import { expect } from 'chai';
 import { BigNumber } from 'ethers';
 import './helpers/math/wadraymath';
@@ -38,7 +39,7 @@ makeSuite('Gho OnBehalf Borrow Flow', (testEnv: TestEnv) => {
       .connect(users[0].signer)
       .approveDelegation(users[1].address, borrowAmount);
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'BorrowAllowanceDelegated')
       .withArgs(users[0].address, users[1].address, gho.address, borrowAmount);
   });
@@ -50,7 +51,7 @@ makeSuite('Gho OnBehalf Borrow Flow', (testEnv: TestEnv) => {
       .connect(users[1].signer)
       .borrow(gho.address, borrowAmount, 2, 0, users[0].address);
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(ZERO_ADDRESS, users[0].address, borrowAmount)
       .to.emit(variableDebtToken, 'Mint')
@@ -113,7 +114,7 @@ makeSuite('Gho OnBehalf Borrow Flow', (testEnv: TestEnv) => {
     );
     const expIndex = variableBorrowIndex.rayMul(multiplier);
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(ZERO_ADDRESS, users[2].address, borrowAmount)
       .to.emit(variableDebtToken, 'Mint')
@@ -158,7 +159,7 @@ makeSuite('Gho OnBehalf Borrow Flow', (testEnv: TestEnv) => {
       .repay(gho.address, user1ExpectedBalance, 2, users[0].address);
     rcpt = await tx.wait();
 
-    expect(tx)
+    await expect(tx)
       .to.emit(variableDebtToken, 'Transfer')
       .withArgs(users[0].address, ZERO_ADDRESS, borrowAmount)
       .to.emit(variableDebtToken, 'Burn')