🤡 mocks: add MockBalancerVault contract

.gas-snapshot

@@ -15,45 +15,46 @@ InterestRateModelTest:testFloatingBorrowRate() (gas: 6236)
 InterestRateModelTest:testMinFixedRate() (gas: 7610)
 InterestRateModelTest:testRevertFixedMaxUtilizationLowerThanWad() (gas: 81593)
 InterestRateModelTest:testRevertFloatingMaxUtilizationLowerThanWad() (gas: 81681)
-LeveragerTest:testApproveMaliciousMarket() (gas: 24153)
+LeveragerTest:testApproveMaliciousMarket() (gas: 24198)
 LeveragerTest:testApproveMarket() (gas: 56626)
 LeveragerTest:testAvailableLiquidity() (gas: 95129)
-LeveragerTest:testCallReceiveFlashLoanFromAnyAddress() (gas: 25074)
+LeveragerTest:testCallReceiveFlashLoanFromAnyAddress() (gas: 25030)
 LeveragerTest:testDeleverage() (gas: 449866)
-LeveragerTest:testDeleverageHalfBorrowPosition() (gas: 488966)
+LeveragerTest:testDeleverageHalfBorrowPosition() (gas: 488989)
 LeveragerTest:testFixedDeleverage() (gas: 429772)
 LeveragerTest:testFixedRoll() (gas: 515399)
 LeveragerTest:testFixedRollSameMaturityWithThreeLoops() (gas: 394620)
 LeveragerTest:testFixedRollWithAccurateBorrowSlippage() (gas: 693262)
 LeveragerTest:testFixedRollWithAccurateBorrowSlippageWithThreeLoops() (gas: 1026387)
 LeveragerTest:testFixedRollWithAccurateRepaySlippage() (gas: 693033)
-LeveragerTest:testFixedRollWithAccurateRepaySlippageWithThreeLoops() (gas: 1020923)
+LeveragerTest:testFixedRollWithAccurateRepaySlippageWithThreeLoops() (gas: 1020901)
 LeveragerTest:testFixedToFloatingRoll() (gas: 461239)
-LeveragerTest:testFixedToFloatingRollHigherThanAvailableLiquidity() (gas: 528322)
+LeveragerTest:testFixedToFloatingRollHigherThanAvailableLiquidity() (gas: 528278)
 LeveragerTest:testFixedToFloatingRollHigherThanAvailableLiquidityWithSlippage() (gas: 722384)
-LeveragerTest:testFixedToFloatingRollHigherThanAvailableLiquidityWithSlippageWithThreeLoops() (gas: 879457)
-LeveragerTest:testFixedToFloatingRollWithAccurateSlippage() (gas: 601851)
-LeveragerTest:testFlashloanFeeGreaterThanZero() (gas: 400935)
+LeveragerTest:testFixedToFloatingRollHigherThanAvailableLiquidityWithSlippageWithThreeLoops() (gas: 879435)
+LeveragerTest:testFixedToFloatingRollWithAccurateSlippage() (gas: 601833)
+LeveragerTest:testFlashloanFeeGreaterThanZero() (gas: 400913)
 LeveragerTest:testFloatingToFixedRoll() (gas: 506215)
 LeveragerTest:testFloatingToFixedRollHigherThanAvailableLiquidity() (gas: 590990)
 LeveragerTest:testFloatingToFixedRollHigherThanAvailableLiquidityWithSlippage() (gas: 895933)
-LeveragerTest:testFloatingToFixedRollHigherThanAvailableLiquidityWithSlippageWithThreePools() (gas: 1105462)
-LeveragerTest:testFloatingToFixedRollWithAccurateSlippage() (gas: 724462)
-LeveragerTest:testFloatingToFixedRollWithAccurateSlippageWithPreviousPosition() (gas: 675363)
+LeveragerTest:testFloatingToFixedRollHigherThanAvailableLiquidityWithSlippageWithThreePools() (gas: 1105440)
+LeveragerTest:testFloatingToFixedRollWithAccurateSlippage() (gas: 724440)
+LeveragerTest:testFloatingToFixedRollWithAccurateSlippageWithPreviousPosition() (gas: 675341)
 LeveragerTest:testLateFixedDeleverage() (gas: 471140)
-LeveragerTest:testLateFixedRoll() (gas: 526122)
+LeveragerTest:testLateFixedRoll() (gas: 526100)
 LeveragerTest:testLateFixedRollWithThreeLoops() (gas: 707888)
 LeveragerTest:testLateFixedToFloatingRoll() (gas: 470476)
-LeveragerTest:testLateFixedToFloatingRollWithThreeLoops() (gas: 633582)
-LeveragerTest:testLeverage() (gas: 365861)
-LeveragerTest:testLeverageShouldFailWhenHealthFactorNearOne() (gas: 719076)
-LeveragerTest:testLeverageWithAlreadyDepositedAmount() (gas: 394241)
-LeveragerTest:testLeverageWithInvalidBalancerVault() (gas: 2691948)
-LeveragerTest:testPartialFixedDeleverage() (gas: 516098)
-LeveragerTest:testPartialFixedRoll() (gas: 578654)
+LeveragerTest:testLateFixedToFloatingRollWithThreeLoops() (gas: 633670)
+LeveragerTest:testLeverage() (gas: 365839)
+LeveragerTest:testLeverageShouldFailWhenHealthFactorNearOne() (gas: 719054)
+LeveragerTest:testLeverageWithAlreadyDepositedAmount() (gas: 394197)
+LeveragerTest:testLeverageWithInvalidBalancerVault() (gas: 2691971)
+LeveragerTest:testMockBalancerVault() (gas: 3727680)
+LeveragerTest:testPartialFixedDeleverage() (gas: 516121)
+LeveragerTest:testPartialFixedRoll() (gas: 578742)
 LeveragerTest:testPartialFixedToFloatingRoll() (gas: 539354)
-LeveragerTest:testPartialLateFixedRoll() (gas: 571143)
-LeveragerTest:testPartialLateFixedToFloatingRoll() (gas: 538030)
+LeveragerTest:testPartialLateFixedRoll() (gas: 571121)
+LeveragerTest:testPartialLateFixedToFloatingRoll() (gas: 538008)
 MarketTest:testAccountLiquidityAdjustedDebt() (gas: 380765)
 MarketTest:testAnotherUserRedeemWhenOwnerHasShortfall() (gas: 483813)
 MarketTest:testAnotherUserWithdrawWhenOwnerHasShortfall() (gas: 472690)

contracts/mocks/MockBalancerVault.sol

@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity 0.8.17;
+
+import { ERC20 } from "solmate/src/tokens/ERC20.sol";
+import { ReentrancyGuard } from "solmate/src/utils/ReentrancyGuard.sol";
+import { SafeTransferLib } from "solmate/src/utils/SafeTransferLib.sol";
+
+contract MockBalancerVault is ReentrancyGuard {
+  using SafeTransferLib for ERC20;
+
+  function flashLoan(
+    IFlashLoanRecipient recipient,
+    ERC20[] memory tokens,
+    uint256[] memory amounts,
+    bytes memory userData
+  ) external nonReentrant {
+    assert(tokens.length == amounts.length);
+
+    uint256[] memory preLoanBalances = new uint256[](tokens.length);
+
+    // Used to ensure `tokens` is sorted in ascending order, which ensures token uniqueness.
+    ERC20 previousToken = ERC20(address(0));
+
+    for (uint256 i = 0; i < tokens.length; ++i) {
+      ERC20 token = tokens[i];
+      uint256 amount = amounts[i];
+
+      require(token > previousToken, token == ERC20(address(0)) ? "Zero token" : "Unsorted tokens");
+      previousToken = token;
+
+      preLoanBalances[i] = token.balanceOf(address(this));
+
+      require(preLoanBalances[i] >= amount, "Insufficient flashloan balance");
+      token.safeTransfer(address(recipient), amount);
+    }
+
+    recipient.receiveFlashLoan(tokens, amounts, new uint256[](tokens.length), userData);
+
+    for (uint256 i = 0; i < tokens.length; ++i) {
+      uint256 postLoanBalance = tokens[i].balanceOf(address(this));
+      require(postLoanBalance >= preLoanBalances[i], "Invalid post flashloan balance");
+    }
+  }
+}
+
+interface IFlashLoanRecipient {
+  function receiveFlashLoan(
+    ERC20[] memory tokens,
+    uint256[] memory amounts,
+    uint256[] memory feeAmounts,
+    bytes memory userData
+  ) external;
+}

test/solidity/Leverager.t.sol

@@ -12,6 +12,7 @@ import {
   InvalidOperation
 } from "../../contracts/periphery/Leverager.sol";
 import { Auditor, Market, InsufficientAccountLiquidity, MarketNotListed } from "../../contracts/Auditor.sol";
+import { MockBalancerVault } from "../../contracts/mocks/MockBalancerVault.sol";
 import { FixedLib } from "../../contracts/utils/FixedLib.sol";
 
 contract LeveragerTest is Test {
@@ -590,6 +591,22 @@ contract LeveragerTest is Test {
     assertEq(availableAssets[1].liquidity, usdc.balanceOf(address(leverager.balancerVault())));
   }
 
+  function testMockBalancerVault() external {
+    MockBalancerVault mockBalancerVault = new MockBalancerVault();
+    leverager = new Leverager(leverager.auditor(), IBalancerVault(address(mockBalancerVault)));
+    marketUSDC.approve(address(leverager), type(uint256).max);
+    marketUSDC.deposit(100_000e6, address(this));
+    marketUSDC.borrow(50_000e6, address(this), address(this));
+
+    vm.expectRevert(bytes(""));
+    leverager.floatingRoll(marketUSDC, true, maturity, type(uint256).max, 1e18);
+
+    deal(address(usdc), address(mockBalancerVault), 50000000001);
+    leverager.floatingRoll(marketUSDC, true, maturity, type(uint256).max, 1e18);
+    (uint256 principal, ) = marketUSDC.fixedBorrowPositions(maturity, address(this));
+    assertEq(principal, 50_000e6 + 1);
+  }
+
   function previewActualRepay(uint256 percentage) internal view returns (uint256 actualRepay) {
     FixedLib.Position memory position;
     (position.principal, position.fee) = marketUSDC.fixedBorrowPositions(maturity, address(this));