test: add permit2 tests for simple swaps in TychoRouter and GasTest

foundry/test/GasTest.t.sol

@@ -30,8 +30,8 @@ contract GasTest is Commands, Test, Constants {
         vm.createSelectFork(vm.rpcUrl("mainnet"), forkBlock);
     }
 
-    // Gas usage: 248717
-    // TychoRouter:testSwapSimple costs 255123
+    // Gas usage: 248511
+    // TychoRouter:testSwapSimple costs 113647
     function testUniversalRouterUniswapV2() public {
         uint256 amountIn = 10 ** 18;
 
@@ -49,8 +49,34 @@ contract GasTest is Commands, Test, Constants {
         universalRouter.execute(commands, inputs, block.timestamp + 1000);
     }
 
-    // Gas usage: 251900
-    // TychoRouter:testSwapSingleUSV3 costs 264195
+    // Gas usage: 296248
+    // TychoRouter:testSwapSimplePermit2 costs 184993
+    function testUniversalRouterUniswapV2Permit2() 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, true);
+
+        deal(WETH_ADDR, address(this), amountIn);
+        IERC20(WETH_ADDR).approve(PERMIT2_ADDRESS, amountIn);
+        permit2.approve(
+            WETH_ADDR,
+            address(universalRouter),
+            uint160(amountIn),
+            uint48(block.timestamp + 1000)
+        );
+        universalRouter.execute(commands, inputs, block.timestamp + 1000);
+    }
+
+    // Gas usage: 252003
+    // TychoRouter:testSwapSingleUSV3 costs 126181
     function testUniversalRouterUniswapV3() public {
         uint256 amountIn = 10 ** 18;
 
@@ -67,9 +93,34 @@ contract GasTest is Commands, Test, Constants {
         universalRouter.execute(commands, inputs, block.timestamp + 1000);
     }
 
-    // Gas usage: 299427
-    // TychoRouter:testSwapSingleUSV4Callback costs 286025
-    function testUniversalRouterUniswapV4() public {
+    // Gas usage: 299036
+    // TychoRouter:testSwapSingleUSV3Permit2 costs 192780
+    function testUniversalRouterUniswapV3Permit2() 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, true);
+
+        deal(WETH_ADDR, address(this), amountIn);
+        IERC20(WETH_ADDR).approve(PERMIT2_ADDRESS, amountIn);
+        permit2.approve(
+            WETH_ADDR,
+            address(universalRouter),
+            uint160(amountIn),
+            uint48(block.timestamp + 1000)
+        );
+        universalRouter.execute(commands, inputs, block.timestamp + 1000);
+    }
+
+    // Gas usage: 299523
+    // TychoRouter:testSwapSingleUSV4CallbackPermit2 costs 217751
+    function testUniversalRouterUniswapV4Permit2() public {
         uint128 amountIn = uint128(100 ether);
         uint128 amountOutMinimum = uint128(0);
         uint256 deadline = block.timestamp + 1000;