test: add GasTest to compare with Universal Router gas usage

foundry/interfaces/IUniversalRouter.sol

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+pragma solidity ^0.8.24;
+
+interface IUniversalRouter {
+    /// @notice Thrown when a required command has failed
+    error ExecutionFailed(uint256 commandIndex, bytes message);
+
+    /// @notice Thrown when attempting to send ETH directly to the contract
+    error ETHNotAccepted();
+
+    /// @notice Thrown when executing commands with an expired deadline
+    error TransactionDeadlinePassed();
+
+    /// @notice Thrown when attempting to execute commands and an incorrect number of inputs are provided
+    error LengthMismatch();
+
+    // @notice Thrown when an address that isn't WETH tries to send ETH to the router without calldata
+    error InvalidEthSender();
+
+    /// @notice Executes encoded commands along with provided inputs. Reverts if deadline has expired.
+    /// @param commands A set of concatenated commands, each 1 byte in length
+    /// @param inputs An array of byte strings containing abi encoded inputs for each command
+    /// @param deadline The deadline by which the transaction must be executed
+    function execute(bytes calldata commands, bytes[] calldata inputs, uint256 deadline) external payable;
+}

foundry/test/Constants.sol

@@ -50,6 +50,12 @@ contract Constants is Test, BaseConstants {
     address USV3_FACTORY = 0x1F98431c8aD98523631AE4a59f267346ea31F984;
     address DAI_WETH_USV3 = 0xC2e9F25Be6257c210d7Adf0D4Cd6E3E881ba25f8;
 
+    // universal router
+    address UNIVERSAL_ROUTER = 0x66a9893cC07D91D95644AEDD05D03f95e1dBA8Af;
+
+    // permit2
+    address PERMIT2_ADDRESS = 0x000000000022D473030F116dDEE9F6B43aC78BA3;
+
     /**
      * @dev Deploys a dummy contract with non-empty bytecode
      */

foundry/test/GasTest.t.sol

@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+pragma solidity ^0.8.24;
+
+import {IUniversalRouter} from "../interfaces/IUniversalRouter.sol";
+import {IPermit2} from "../lib/permit2/src/interfaces/IPermit2.sol";
+import {Constants} from "./Constants.sol";
+import {Actions} from "../lib/v4-periphery/src/libraries/Actions.sol";
+import {PoolKey} from "../lib/v4-core/src/types/PoolKey.sol";
+import {IV4Router} from "../lib/v4-periphery/src/interfaces/IV4Router.sol";
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import {Currency} from "../lib/v4-core/src/types/Currency.sol";
+import {IHooks} from "../lib/v4-core/src/interfaces/IHooks.sol";
+import "forge-std/Test.sol";
+
+contract Commands {
+    uint256 constant V2_SWAP_EXACT_IN = 0x08;
+    uint256 constant V3_SWAP_EXACT_IN = 0x00;
+    uint256 constant V4_SWAP = 0x10;
+}
+
+// A gas test to compare the gas usage of the UniversalRouter with the TychoRouter
+// The gas usage quoted from the TychoRouter is without any asserts after the swap
+// The path executed on TychoRouter is the same as the path executed on UniversalRouter
+contract GasTest is Commands, Test, Constants {
+    IUniversalRouter universalRouter = IUniversalRouter(UNIVERSAL_ROUTER);
+    IPermit2 permit2 = IPermit2(PERMIT2_ADDRESS);
+
+    function setUp() public {
+        uint256 forkBlock = 21817316;
+        vm.createSelectFork(vm.rpcUrl("mainnet"), forkBlock);
+    }
+
+    // Gas usage: 248717
+    // TychoRouter:testSwapSimple costs 255123
+    function testUniversalRouterUniswapV2() public {
+        uint256 amountIn = 10 ** 18;
+
+        bytes memory commands =
+            abi.encodePacked(uint8(Commands.V2_SWAP_EXACT_IN));
+
+        address[] memory path = new address[](2);
+        path[0] = WETH_ADDR;
+        path[1] = DAI_ADDR;
+
+        bytes[] memory inputs = new bytes[](1);
+        inputs[0] = abi.encode(BOB, amountIn, uint256(0), path, false);
+
+        deal(WETH_ADDR, address(universalRouter), amountIn);
+        universalRouter.execute(commands, inputs, block.timestamp + 1000);
+    }
+
+    // Gas usage: 251900
+    // TychoRouter:testSwapSingleUSV3 costs 264195
+    function testUniversalRouterUniswapV3() public {
+        uint256 amountIn = 10 ** 18;
+
+        bytes memory commands =
+            abi.encodePacked(uint8(Commands.V3_SWAP_EXACT_IN));
+
+        uint24 poolFee = 3000;
+        bytes memory path = abi.encodePacked(WETH_ADDR, poolFee, DAI_ADDR);
+
+        bytes[] memory inputs = new bytes[](1);
+        inputs[0] = abi.encode(BOB, amountIn, uint256(0), path, false);
+
+        deal(WETH_ADDR, address(universalRouter), amountIn);
+        universalRouter.execute(commands, inputs, block.timestamp + 1000);
+    }
+
+    // Gas usage: 299427
+    // TychoRouter:testSwapSingleUSV4Callback costs 286025
+    function testUniversalRouterUniswapV4() public {
+        uint128 amountIn = uint128(100 ether);
+        uint128 amountOutMinimum = uint128(0);
+        uint256 deadline = block.timestamp + 1000;
+
+        bytes memory commands = abi.encodePacked(uint8(Commands.V4_SWAP));
+
+        bytes memory actions = abi.encodePacked(
+            uint8(Actions.SWAP_EXACT_IN_SINGLE),
+            uint8(Actions.SETTLE_ALL),
+            uint8(Actions.TAKE_ALL)
+        );
+
+        PoolKey memory key = PoolKey({
+            currency0: Currency.wrap(USDE_ADDR),
+            currency1: Currency.wrap(USDT_ADDR),
+            fee: 100,
+            tickSpacing: int24(1),
+            hooks: IHooks(address(0))
+        });
+
+        bytes[] memory params = new bytes[](3);
+        params[0] = abi.encode(
+            IV4Router.ExactInputSingleParams({
+                poolKey: key,
+                zeroForOne: true,
+                amountIn: amountIn,
+                amountOutMinimum: amountOutMinimum,
+                hookData: bytes("")
+            })
+        );
+
+        params[1] = abi.encode(key.currency0, amountIn);
+        params[2] = abi.encode(key.currency1, amountOutMinimum);
+
+        bytes[] memory inputs = new bytes[](1);
+        inputs[0] = abi.encode(actions, params);
+
+        deal(USDE_ADDR, address(this), amountIn);
+        IERC20(USDE_ADDR).approve(PERMIT2_ADDRESS, amountIn);
+        permit2.approve(
+            USDE_ADDR, address(universalRouter), amountIn, uint48(deadline)
+        );
+        universalRouter.execute(commands, inputs, deadline);
+    }
+}

foundry/test/TychoRouter.t.sol

@@ -650,7 +650,7 @@ contract TychoRouterTest is TychoRouterTestSetup {
 
         // Approve permit2
         vm.startPrank(ALICE);
-        IERC20(WETH_ADDR).approve(address(permit2Address), type(uint256).max);
+        IERC20(WETH_ADDR).approve(PERMIT2_ADDRESS, type(uint256).max);
         // Encoded solution generated using `test_split_swap_strategy_encoder_simple`
         // but manually replacing the executor address
         // `5c2f5a71f67c01775180adc06909288b4c329308` with the one in this test
@@ -688,7 +688,7 @@ contract TychoRouterTest is TychoRouterTestSetup {
         assertEq(balancerAfter - balancerBefore, 2659881924818443699787);
     }
 
-    function testUSV4Integration4() public {
+    function testUSV4Integration() public {
         // Test created with calldata from our router encoder.
 
         // Performs a sequential swap from USDC to PEPE though ETH using two
@@ -701,7 +701,7 @@ contract TychoRouterTest is TychoRouterTestSetup {
 
         // Approve permit2
         vm.startPrank(ALICE);
-        IERC20(USDC_ADDR).approve(address(permit2Address), type(uint256).max);
+        IERC20(USDC_ADDR).approve(PERMIT2_ADDRESS, type(uint256).max);
         // Encoded solution generated using `test_split_encoding_strategy_usv4`
         // and ensuring that the encoded executor address is the one in this test
         // `f62849f9a0b5bf2913b396098f7c7019b51a820a`
@@ -754,7 +754,7 @@ contract TychoRouterTest is TychoRouterTestSetup {
 
         // Approve permit2
         vm.startPrank(ALICE);
-        IERC20(USDC_ADDR).approve(address(permit2Address), type(uint256).max);
+        IERC20(USDC_ADDR).approve(PERMIT2_ADDRESS, type(uint256).max);
 
         // Encoded solution generated using `test_split_encoding_strategy_usv4_eth_out`
         // and ensuring that the encoded executor address is the one in this test
@@ -783,7 +783,7 @@ contract TychoRouterTest is TychoRouterTestSetup {
 
         // Approve permit2
         vm.startPrank(ALICE);
-        //        IERC20(WETH_ADDR).approve(address(permit2Address), type(uint256).max);
+        //        IERC20(WETH_ADDR).approve(PERMIT2_ADDRESS, type(uint256).max);
         // Encoded solution generated using
         // `test_split_swap_strategy_encoder_simple_route_wrap`
         // but manually replacing the executor address
@@ -812,7 +812,7 @@ contract TychoRouterTest is TychoRouterTestSetup {
 
         // Approve permit2
         vm.startPrank(ALICE);
-        IERC20(DAI_ADDR).approve(address(permit2Address), type(uint256).max);
+        IERC20(DAI_ADDR).approve(PERMIT2_ADDRESS, type(uint256).max);
         // Encoded solution generated using
         // `test_split_swap_strategy_encoder_simple_route_unwrap`
         // but manually replacing the executor address
@@ -844,7 +844,7 @@ contract TychoRouterTest is TychoRouterTestSetup {
 
         // Approve permit2
         vm.startPrank(ALICE);
-        IERC20(WETH_ADDR).approve(address(permit2Address), type(uint256).max);
+        IERC20(WETH_ADDR).approve(PERMIT2_ADDRESS, type(uint256).max);
         // Encoded solution generated using `test_split_swap_strategy_encoder_complex`
         // but manually replacing the executor address
         // `5c2f5a71f67c01775180adc06909288b4c329308` with the one in this test

foundry/test/TychoRouterTestSetup.sol

@@ -34,7 +34,6 @@ contract TychoRouterExposed is TychoRouter {
 contract TychoRouterTestSetup is Test, Constants {
     TychoRouterExposed tychoRouter;
     address tychoRouterAddr;
-    address permit2Address = address(0x000000000022D473030F116dDEE9F6B43aC78BA3);
     UniswapV2Executor public usv2Executor;
     UniswapV3Executor public usv3Executor;
     UniswapV4Executor public usv4Executor;
@@ -48,7 +47,7 @@ contract TychoRouterTestSetup is Test, Constants {
         address factoryV3 = USV3_FACTORY;
         address poolManagerAddress = 0x000000000004444c5dc75cB358380D2e3dE08A90;
         IPoolManager poolManager = IPoolManager(poolManagerAddress);
-        tychoRouter = new TychoRouterExposed(permit2Address, WETH_ADDR);
+        tychoRouter = new TychoRouterExposed(PERMIT2_ADDRESS, WETH_ADDR);
         tychoRouterAddr = address(tychoRouter);
         tychoRouter.grantRole(keccak256("FUND_RESCUER_ROLE"), FUND_RESCUER);
         tychoRouter.grantRole(keccak256("FEE_SETTER_ROLE"), FEE_SETTER);
@@ -107,7 +106,7 @@ contract TychoRouterTestSetup is Test, Constants {
         internal
         returns (IAllowanceTransfer.PermitSingle memory, bytes memory)
     {
-        IERC20(tokenIn).approve(permit2Address, amount_in);
+        IERC20(tokenIn).approve(PERMIT2_ADDRESS, amount_in);
         IAllowanceTransfer.PermitSingle memory permitSingle = IAllowanceTransfer
             .PermitSingle({
             details: IAllowanceTransfer.PermitDetails({
@@ -147,7 +146,7 @@ contract TychoRouterTestSetup is Test, Constants {
                 ),
                 keccak256("Permit2"),
                 block.chainid,
-                permit2Address
+                PERMIT2_ADDRESS
             )
         );
         bytes32 detailsHash =