test: initialize echidna for fuzz testing

.eslintignore

@@ -4,4 +4,5 @@ cache
 dist
 node_modules
 typechain-types
-docs
+docs
+crytic-export

.gitignore

@@ -30,4 +30,6 @@ coverage.json
 scripts/slither-results/*
 !scripts/slither-results/.gitkeep
 
-abi
+abi
+
+crytic-export

contracts/prototypes/evm/ERC20CustodyNew.sol

@@ -38,12 +38,12 @@
     // For this, it passes through the Gateway contract, it transfers the tokens to the Gateway contract and then calls the contract
     // TODO: Finalize access control
     // https://github.com/zeta-chain/protocol-contracts/issues/204
-    function withdrawAndCall(address token, address to, uint256 amount, bytes calldata data) external nonReentrant {
+    function withdrawAndCall(address token, address to, uint256 amount, bytes calldata data) public nonReentrant {
         // Transfer the tokens to the Gateway contract
         IERC20(token).safeTransfer(address(gateway), amount);
 
         // Forward the call to the Gateway contract
         gateway.executeWithERC20(token, to, amount, data);
 
         emit WithdrawAndCall(token, to, amount, data);
     }

contracts/prototypes/evm/GatewayEVM.sol

@@ -18,6 +18,7 @@ contract GatewayEVM is Initializable, OwnableUpgradeable, UUPSUpgradeable {
     error InsufficientERC20Amount();
     error ZeroAddress();
     error ApprovalFailed();
+    error CustodyInitialized();
 
     address public custody;
     address public tssAddress;
@@ -27,9 +28,7 @@ contract GatewayEVM is Initializable, OwnableUpgradeable, UUPSUpgradeable {
     event Deposit(address indexed sender, address indexed receiver, uint256 amount, address asset, bytes payload);
     event Call(address indexed sender, address indexed receiver, bytes payload);
 
-    /// @custom:oz-upgrades-unsafe-allow constructor
     constructor() {
-        _disableInitializers();
     }
 
     function initialize(address _tssAddress) public initializer {
@@ -71,7 +70,7 @@ contract GatewayEVM is Initializable, OwnableUpgradeable, UUPSUpgradeable {
         address to,
         uint256 amount,
         bytes calldata data
-    ) external returns (bytes memory) {
+    ) public returns (bytes memory) {
         if (amount == 0) revert InsufficientETHAmount();
         // Approve the target contract to spend the tokens
         if(!resetApproval(token, to)) revert ApprovalFailed();
@@ -136,6 +135,7 @@ contract GatewayEVM is Initializable, OwnableUpgradeable, UUPSUpgradeable {
     }
 
     function setCustody(address _custody) external {
+        if (custody != address(0)) revert CustodyInitialized();
         custody = _custody;
     }
 

echidna.yaml

@@ -0,0 +1,6 @@
+# provide solc remappings to crytic-compile
+cryticArgs: ['--solc-remaps', '@=node_modules/@']
+testMode: "assertion"
+testLimit: 50000  
+seqLen: 10000 
+allContracts: false

test/fuzz/ERC20CustodyNewEchidnaTest.sol

@@ -0,0 +1,32 @@
+import "../../contracts/prototypes/evm/TestERC20.sol";
+import "../../contracts/prototypes/evm/ERC20CustodyNew.sol";
+import "../../contracts/prototypes/evm/GatewayEVM.sol";
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+
+contract ERC20CustodyNewEchidnaTest is ERC20CustodyNew {
+    using SafeERC20 for IERC20;
+
+    TestERC20 public testERC20;
+    address public echidnaCaller = msg.sender;
+
+    GatewayEVM testGateway = new GatewayEVM();
+
+    constructor() ERC20CustodyNew(address(testGateway)) {
+        testGateway.initialize(echidnaCaller);
+        testERC20 = new TestERC20("test", "TEST");
+        testGateway.setCustody(address(this));
+    }
+
+    function testWithdrawAndCall(address to, uint256 amount, bytes calldata data) public {
+        // mint more than amount
+        testERC20.mint(address(this), amount + 5);
+        // transfer overhead to gateway
+        testERC20.transfer(address(testGateway), 5);
+
+        withdrawAndCall(address(testERC20), to, amount, data);
+
+        // Assertion to ensure no ERC20 tokens are left in the gateway contract after execution
+        assert(testERC20.balanceOf(address(gateway)) == 0);
+    }
+}

test/fuzz/GatewayEVMEchidnaTest.sol

@@ -0,0 +1,27 @@
+import "../../contracts/prototypes/evm/GatewayEVM.sol";
+import "../../contracts/prototypes/evm/TestERC20.sol";
+import "../../contracts/prototypes/evm/ERC20CustodyNew.sol";
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+
+contract GatewayEVMEchidnaTest is GatewayEVM {
+    using SafeERC20 for IERC20;
+
+    TestERC20 public testERC20;
+    address public echidnaCaller = msg.sender;
+
+    constructor() {
+        initialize(echidnaCaller);
+        testERC20 = new TestERC20("test", "TEST");
+        custody = address(new ERC20CustodyNew(address(this)));
+    }
+
+    function testExecuteWithERC20(address to, uint256 amount, bytes calldata data) public {
+        testERC20.mint(address(this), amount);
+
+        executeWithERC20(address(testERC20), to, amount, data);
+
+        // Assertion to ensure no ERC20 tokens are left in the contract after execution
+        assert(testERC20.balanceOf(address(this)) == 0);
+    }
+}

test/fuzz/readme.md

@@ -0,0 +1,13 @@
+## Setup echidna
+
+```
+brew install echidna
+solc-select use 0.8.7
+```
+
+## Execute contract tests
+
+```
+echidna test/fuzz/ERC20CustodyNewEchidnaTest.sol --contract ERC20CustodyNewEchidnaTest  --config echidna.yaml
+echidna test/fuzz/GatewayEVMEchidnaTest.sol --contract GatewayEVMEchidnaTest  --config echidna.yaml
+```