chore: migrate E2E buyEth tests to Foundry

test/e2e/BuyEth.t.sol

@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+pragma solidity ^0.8;
+
+import {Vm} from "forge-std/Vm.sol";
+
+import {IERC20} from "src/contracts/interfaces/IERC20.sol";
+import {GPv2Transfer} from "src/contracts/libraries/GPv2Transfer.sol";
+
+import {
+    GPv2Interaction, GPv2Order, GPv2Signing, SettlementEncoder
+} from "test/libraries/encoders/SettlementEncoder.sol";
+import {Registry, TokenRegistry} from "test/libraries/encoders/TokenRegistry.sol";
+
+import {Helper} from "./Helper.sol";
+
+interface IUSDT {
+    function getOwner() external view returns (address);
+    function issue(uint256) external;
+    // approve and transfer doesn't return the bool for USDT
+    function approve(address, uint256) external;
+    function transfer(address, uint256) external;
+}
+
+IUSDT constant USDT = IUSDT(0xdAC17F958D2ee523a2206206994597C13D831ec7);
+IERC20 constant WETH = IERC20(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
+
+using SettlementEncoder for SettlementEncoder.State;
+using TokenRegistry for TokenRegistry.State;
+using TokenRegistry for Registry;
+
+contract BuyEthTest is Helper(true) {
+    // Settle a trivial batch between two overlapping trades:
+    //
+    //   /----(1. SELL 1 WETH for USDT if p(WETH) >= 1100)----\
+    //   |                                                    v
+    // [USDT]                                              [(W)ETH]
+    //   ^                                                    |
+    //   \-----(2. BUY 1 ETH for USDT if p(WETH) <= 1200)-----/
+    function test_should_unwrap_weth_for_eth_buy_orders() external {
+        Vm.Wallet memory trader1 = vm.createWallet("trader1");
+        Vm.Wallet memory trader2 = vm.createWallet("trader2");
+
+        // give some weth to trader1
+        deal(address(WETH), trader1.addr, 1.001 ether);
+        // approve weth for trading on the vault
+        vm.prank(trader1.addr);
+        WETH.approve(vaultRelayer, type(uint256).max);
+        // place the weth to usdt swap order
+        encoder.signEncodeTrade(
+            vm,
+            trader1,
+            GPv2Order.Data({
+                sellToken: WETH,
+                buyToken: IERC20(address(USDT)),
+                receiver: trader1.addr,
+                sellAmount: 1 ether,
+                buyAmount: 1100e6,
+                validTo: 0xffffffff,
+                appData: bytes32(uint256(1)),
+                feeAmount: 0.001 ether,
+                kind: GPv2Order.KIND_SELL,
+                partiallyFillable: false,
+                sellTokenBalance: GPv2Order.BALANCE_ERC20,
+                buyTokenBalance: GPv2Order.BALANCE_ERC20
+            }),
+            domainSeparator,
+            GPv2Signing.Scheme.Eip712,
+            0
+        );
+
+        // give some usdt to trader2
+        _mintUsdt(trader2.addr, 1201.2e6);
+        // approve usdt for trading on the vault
+        vm.prank(trader2.addr);
+        USDT.approve(vaultRelayer, type(uint256).max);
+        // place the usdt to eth swap order
+        encoder.signEncodeTrade(
+            vm,
+            trader2,
+            GPv2Order.Data({
+                sellToken: IERC20(address(USDT)),
+                buyToken: IERC20(GPv2Transfer.BUY_ETH_ADDRESS),
+                receiver: trader2.addr,
+                sellAmount: 1200e6,
+                buyAmount: 1 ether,
+                validTo: 0xffffffff,
+                appData: bytes32(uint256(1)),
+                feeAmount: 1.2e6,
+                kind: GPv2Order.KIND_BUY,
+                partiallyFillable: false,
+                sellTokenBalance: GPv2Order.BALANCE_ERC20,
+                buyTokenBalance: GPv2Order.BALANCE_ERC20
+            }),
+            domainSeparator,
+            GPv2Signing.Scheme.Eip712,
+            0
+        );
+
+        // encode the weth withdraw interaction
+        encoder.addInteraction(
+            GPv2Interaction.Data({
+                target: address(WETH),
+                value: 0,
+                callData: abi.encodeWithSignature("withdraw(uint256)", 1 ether)
+            }),
+            SettlementEncoder.InteractionStage.INTRA
+        );
+
+        // set the token prices
+        IERC20[] memory tokens = new IERC20[](3);
+        tokens[0] = WETH;
+        tokens[1] = IERC20(GPv2Transfer.BUY_ETH_ADDRESS);
+        tokens[2] = IERC20(address(USDT));
+        uint256[] memory prices = new uint256[](3);
+        prices[0] = 1150e6;
+        prices[1] = 1150e6;
+        prices[2] = 1 ether;
+        encoder.tokenRegistry.tokenRegistry().setPrices(tokens, prices);
+
+        SettlementEncoder.EncodedSettlement memory encodedSettlement = encoder.encode(settlement);
+
+        uint256 trader2InitialBalance = trader2.addr.balance;
+        vm.prank(solver);
+        settle(encodedSettlement);
+        assertEq(
+            WETH.balanceOf(address(settlement)),
+            0.001 ether,
+            "settlement contract's weth balance from trade fee not as expected"
+        ); // the fee
+        assertEq(WETH.balanceOf(trader1.addr), 0, "trader1 weth balance is not 0");
+        assertEq(
+            trader2.addr.balance, trader2InitialBalance + 1 ether, "trader2 eth balance did not increase as expected"
+        );
+    }
+
+    function _mintUsdt(address receiver, uint256 amt) internal {
+        address owner = USDT.getOwner();
+        vm.startPrank(owner);
+        USDT.issue(amt);
+        USDT.transfer(receiver, amt);
+        vm.stopPrank();
+    }
+}