mev-beta/tests/contracts/FlashLoanReceiverSecure.integration.t.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "forge-std/Test.sol";
import "../../contracts/balancer/FlashLoanReceiverSecure.sol";

/// @title Integration Tests with Real Arbitrum Mainnet Data
/// @notice Tests against actual deployed contracts on Arbitrum
/// @dev Requires forking from Arbitrum mainnet
contract FlashLoanReceiverSecureIntegrationTest is Test {
    FlashLoanReceiverSecure public flashLoan;

    // Real Arbitrum mainnet addresses
    address constant BALANCER_VAULT = 0xBA12222222228d8Ba445958a75a0704d566BF2C8;
    address constant WETH = 0x82aF49447D8a07e3bd95BD0d56f35241523fBab1;
    address constant USDC = 0xaf88d065e77c8cC2239327C5EDb3A432268e5831;
    address constant USDT = 0xFd086bC7CD5C481DCC9C85ebE478A1C0b69FCbb9;
    address constant ARB = 0x912CE59144191C1204E64559FE8253a0e49E6548;
    address constant DAI = 0xDA10009cBd5D07dd0CeCc66161FC93D7c9000da1;

    // Real DEX addresses
    address constant UNISWAP_V3_ROUTER = 0xE592427A0AEce92De3Edee1F18E0157C05861564;
    address constant SUSHISWAP_ROUTER = 0x1b02dA8Cb0d097eB8D57A175b88c7D8b47997506;

    // Whale addresses with large token balances
    address constant WETH_WHALE = 0xF977814e90dA44bFA03b6295A0616a897441aceC; // Binance
    address constant USDC_WHALE = 0x47c031236e19d024b42f8AE6780E44A573170703; // Bridge
    address constant ARB_WHALE = 0xF3FC178157fb3c87548bAA86F9d24BA38E649B58; // Arbitrum Foundation

    address public owner;
    address public user;

    function setUp() public {
        // Fork Arbitrum mainnet (requires ARBITRUM_RPC_URL env var)
        string memory rpcUrl = vm.envString("ARBITRUM_RPC_URL");
        uint256 forkId = vm.createFork(rpcUrl);
        vm.selectFork(forkId);

        // Verify we're on Arbitrum
        require(block.chainid == 42161, "Not on Arbitrum mainnet");

        owner = address(this);
        user = address(0x123);

        // Deploy FlashLoanReceiverSecure with real Balancer Vault
        flashLoan = new FlashLoanReceiverSecure(BALANCER_VAULT);

        // Fund contract with ETH for gas
        vm.deal(address(flashLoan), 10 ether);
    }

    // Allow test contract to receive ETH
    receive() external payable {}

    /// ============================================
    /// REAL CONTRACT INTERACTION TESTS
    /// ============================================

    function testIntegration_RealBalancerVault() public view {
        // Verify we're using the real Balancer Vault
        assertEq(address(flashLoan.vault()), BALANCER_VAULT);

        // Verify Balancer Vault has code (is deployed)
        uint256 size;
        address vaultAddr = BALANCER_VAULT;
        assembly {
            size := extcodesize(vaultAddr)
        }
        assertGt(size, 0, "Balancer Vault not deployed");
    }

    function testIntegration_RealTokenBalances() public {
        // Check real token balances of whales
        uint256 wethBalance = IERC20(WETH).balanceOf(WETH_WHALE);
        uint256 usdcBalance = IERC20(USDC).balanceOf(USDC_WHALE);
        uint256 arbBalance = IERC20(ARB).balanceOf(ARB_WHALE);

        assertGt(wethBalance, 0, "WETH whale has no balance");
        assertGt(usdcBalance, 0, "USDC whale has no balance");
        assertGt(arbBalance, 0, "ARB whale has no balance");

        emit log_named_decimal_uint("WETH Whale Balance", wethBalance, 18);
        emit log_named_decimal_uint("USDC Whale Balance", usdcBalance, 6);
        emit log_named_decimal_uint("ARB Whale Balance", arbBalance, 18);
    }

    function testIntegration_RealTokenMetadata() public {
        // Verify real token properties
        assertEq(IERC20Metadata(WETH).decimals(), 18, "WETH decimals");
        assertEq(IERC20Metadata(USDC).decimals(), 6, "USDC decimals");
        assertEq(IERC20Metadata(USDT).decimals(), 6, "USDT decimals");
        assertEq(IERC20Metadata(ARB).decimals(), 18, "ARB decimals");
        assertEq(IERC20Metadata(DAI).decimals(), 18, "DAI decimals");

        assertEq(IERC20Metadata(WETH).symbol(), "WETH", "WETH symbol");
        assertEq(IERC20Metadata(USDC).symbol(), "USDC", "USDC symbol");
        assertEq(IERC20Metadata(ARB).symbol(), "ARB", "ARB symbol");
    }

    /// ============================================
    /// REAL FLASH LOAN TESTS
    /// ============================================

    function testIntegration_SmallFlashLoan() public {
        // Borrow 1 WETH from Balancer
        uint256 loanAmount = 1 ether;

        // Prepare flash loan parameters
        IERC20[] memory tokens = new IERC20[](1);
        tokens[0] = IERC20(WETH);

        uint256[] memory amounts = new uint256[](1);
        amounts[0] = loanAmount;

        // Create simple arbitrage path (just for testing repayment)
        bytes memory userData = _createSimpleTestPath();

        // Record initial balances
        uint256 vaultWETHBefore = IERC20(WETH).balanceOf(BALANCER_VAULT);

        // Execute flash loan
        vm.prank(owner);
        // Note: This will fail because we need a profitable path
        // But it tests the real Balancer Vault interaction
        vm.expectRevert(); // Will revert with "Insufficient funds for repayment"
        flashLoan.executeArbitrage(tokens, amounts, userData);

        // Verify vault balance unchanged (flash loan reverted)
        assertEq(IERC20(WETH).balanceOf(BALANCER_VAULT), vaultWETHBefore);
    }

    function testIntegration_MultiTokenFlashLoan() public {
        // Borrow multiple tokens
        IERC20[] memory tokens = new IERC20[](2);
        tokens[0] = IERC20(WETH);
        tokens[1] = IERC20(USDC);

        uint256[] memory amounts = new uint256[](2);
        amounts[0] = 0.1 ether;
        amounts[1] = 100 * 10**6; // 100 USDC

        bytes memory userData = _createSimpleTestPath();

        // Execute flash loan (will fail without profitable path)
        vm.prank(owner);
        vm.expectRevert();
        flashLoan.executeArbitrage(tokens, amounts, userData);
    }

    /// ============================================
    /// REAL TOKEN TRANSFER TESTS
    /// ============================================

    function testIntegration_ReceiveRealWETH() public {
        uint256 amount = 1 ether;

        // Impersonate WETH whale
        vm.startPrank(WETH_WHALE);

        // Transfer WETH to contract
        IERC20(WETH).transfer(address(flashLoan), amount);
        vm.stopPrank();

        // Verify transfer
        assertEq(IERC20(WETH).balanceOf(address(flashLoan)), amount);
    }

    function testIntegration_WithdrawRealWETH() public {
        uint256 amount = 0.5 ether;

        // Fund contract with real WETH
        vm.prank(WETH_WHALE);
        IERC20(WETH).transfer(address(flashLoan), amount);

        uint256 ownerBalanceBefore = IERC20(WETH).balanceOf(owner);

        // Withdraw WETH
        flashLoan.withdrawProfit(WETH, amount);

        assertEq(IERC20(WETH).balanceOf(owner), ownerBalanceBefore + amount);
        assertEq(IERC20(WETH).balanceOf(address(flashLoan)), 0);
    }

    function testIntegration_EmergencyWithdrawRealTokens() public {
        // Fund contract with multiple real tokens
        vm.prank(WETH_WHALE);
        IERC20(WETH).transfer(address(flashLoan), 0.1 ether);

        vm.prank(USDC_WHALE);
        IERC20(USDC).transfer(address(flashLoan), 100 * 10**6);

        // Emergency withdraw WETH
        uint256 wethAmount = IERC20(WETH).balanceOf(address(flashLoan));
        flashLoan.emergencyWithdraw(WETH);
        assertEq(IERC20(WETH).balanceOf(address(flashLoan)), 0);
        assertGt(IERC20(WETH).balanceOf(owner), 0);

        // Emergency withdraw USDC
        uint256 usdcAmount = IERC20(USDC).balanceOf(address(flashLoan));
        flashLoan.emergencyWithdraw(USDC);
        assertEq(IERC20(USDC).balanceOf(address(flashLoan)), 0);
        assertGt(IERC20(USDC).balanceOf(owner), 0);
    }

    /// ============================================
    /// REAL DEX INTERACTION TESTS
    /// ============================================

    function testIntegration_UniswapV3RouterExists() public {
        // Verify Uniswap V3 Router is deployed
        uint256 size;
        address router = UNISWAP_V3_ROUTER;
        assembly {
            size := extcodesize(router)
        }
        assertGt(size, 0, "Uniswap V3 Router not deployed");
    }

    function testIntegration_SushiswapRouterExists() public {
        // Verify SushiSwap Router is deployed
        uint256 size;
        address router = SUSHISWAP_ROUTER;
        assembly {
            size := extcodesize(router)
        }
        assertGt(size, 0, "SushiSwap Router not deployed");
    }

    /// ============================================
    /// REAL LIQUIDITY TESTS
    /// ============================================

    function testIntegration_BalancerHasLiquidity() public {
        // Check Balancer Vault has significant WETH liquidity for flash loans
        uint256 wethBalance = IERC20(WETH).balanceOf(BALANCER_VAULT);
        uint256 usdcBalance = IERC20(USDC).balanceOf(BALANCER_VAULT);

        assertGt(wethBalance, 100 ether, "Insufficient WETH liquidity");
        assertGt(usdcBalance, 100_000 * 10**6, "Insufficient USDC liquidity");

        emit log_named_decimal_uint("Balancer WETH Liquidity", wethBalance, 18);
        emit log_named_decimal_uint("Balancer USDC Liquidity", usdcBalance, 6);
    }

    /// ============================================
    /// REAL PRICE ORACLE TESTS
    /// ============================================

    function testIntegration_TokenPriceConsistency() public {
        // Get real token balances from whales
        uint256 wethBalance = IERC20(WETH).balanceOf(WETH_WHALE);
        uint256 usdcBalance = IERC20(USDC).balanceOf(USDC_WHALE);

        // Basic sanity checks
        assertGt(wethBalance, 10 ether, "WETH whale balance too low");
        assertGt(usdcBalance, 10_000 * 10**6, "USDC whale balance too low");

        emit log("Real token balances verified");
    }

    /// ============================================
    /// CONTRACT STATE VERIFICATION
    /// ============================================

    function testIntegration_ContractConfiguration() public view {
        // Verify contract is properly configured
        assertEq(flashLoan.owner(), owner);
        assertEq(address(flashLoan.vault()), BALANCER_VAULT);
        assertEq(flashLoan.MAX_SLIPPAGE_BPS(), 50);
        assertEq(flashLoan.MAX_PATH_LENGTH(), 5);
        assertEq(flashLoan.BASIS_POINTS(), 10000);
    }

    function testIntegration_ContractHasGas() public view {
        // Verify contract has ETH for gas
        assertGt(address(flashLoan).balance, 0);
    }

    /// ============================================
    /// HELPER FUNCTIONS
    /// ============================================

    function _createSimpleTestPath() private pure returns (bytes memory) {
        // Create minimal path structure for testing
        // This is intentionally unprofitable to test flash loan mechanics
        address[] memory tokens = new address[](2);
        tokens[0] = WETH;
        tokens[1] = USDC;

        address[] memory exchanges = new address[](1);
        exchanges[0] = UNISWAP_V3_ROUTER;

        uint24[] memory fees = new uint24[](1);
        fees[0] = 3000; // 0.3% fee tier

        bool[] memory isV3 = new bool[](1);
        isV3[0] = true;

        return abi.encode(
            tokens,
            exchanges,
            fees,
            isV3,
            0, // minProfit
            50 // slippageBps
        );
    }
}

interface IERC20Metadata {
    function decimals() external view returns (uint8);
    function symbol() external view returns (string memory);
    function name() external view returns (string memory);
}