[ZeroEx] add test for Otc order signed by another address

.forge-snapshots/zeroEx_otcOrder_DAI-WETH.snap

@@ -1 +1 @@
-93071
+78527

.forge-snapshots/zeroEx_otcOrder_USDC-WETH.snap

@@ -1 +1 @@
-112545
+98001

.forge-snapshots/zeroEx_otcOrder_USDT-WETH.snap

@@ -1 +1 @@
-104183
+89639

.forge-snapshots/zeroEx_otcOrder_allowedSigner_DAI-WETH.snap

@@ -0,0 +1 @@
+80812

.forge-snapshots/zeroEx_otcOrder_allowedSigner_USDC-WETH.snap

@@ -0,0 +1 @@
+100286

.forge-snapshots/zeroEx_otcOrder_allowedSigner_USDT-WETH.snap

@@ -0,0 +1 @@
+91924

test/integration/BasePairTest.t.sol

@@ -18,6 +18,8 @@ abstract contract BasePairTest is Test, GasSnapshot, Permit2Signature {
     address internal FROM = vm.addr(FROM_PRIVATE_KEY);
     uint256 internal constant MAKER_PRIVATE_KEY = 0x0ff1c1a1;
     address internal MAKER = vm.addr(MAKER_PRIVATE_KEY);
+    uint256 internal constant OTHER_MAKER_PRIVATE_KEY = 0x0cacacac;
+    address internal OTHER_MAKER = vm.addr(OTHER_MAKER_PRIVATE_KEY);
 
     address internal constant BURN_ADDRESS = 0x2222222222222222222222222222222222222222;
 
@@ -78,11 +80,23 @@ abstract contract BasePairTest is Test, GasSnapshot, Permit2Signature {
     function warmZeroExOtcNonce(address who) internal {
         // mapping(address => mapping(uint64 => uint128)) txOriginNonces;
         //        tx.origin          bucket    min nonce
-        // OtcOrders is 8th in LibStorage Enum
+        // OtcOrders is LibStorage[8] Enum https://github.com/0xProject/protocol/blob/master/contracts/zero-ex/contracts/src/storage/LibStorage.sol#L26
         bytes32 slotId = keccak256(abi.encode(uint256(0), keccak256(abi.encode(who, (uint256(8) + 1) << 128))));
         vm.store(address(ZERO_EX_ADDRESS), slotId, bytes32(uint256(1)));
     }
 
+    /// @dev Manually set a registered signer in 0xV4 Native Orders
+    /// note: we attempt to avoid touching storage by the usual means to side
+    /// step gas metering
+    function allowRegisteredSigner(address maker, address signer) internal {
+        // mapping(address => mapping(address => bool)) orderSignerRegistry;
+        //         maker              signer     allowed
+        // NativeOrders is LibStorage[7] Enum https://github.com/0xProject/protocol/blob/master/contracts/zero-ex/contracts/src/storage/LibStorage.sol#L26
+        // orderSignerRegistry is Storage[4] in the Storage struct https://github.com/0xProject/protocol/blob/master/contracts/zero-ex/contracts/src/storage/LibNativeOrdersStorage.sol#L38
+        bytes32 slotId = keccak256(abi.encode(signer, keccak256(abi.encode(maker, ((uint256(7) + 1) << 128) + 4))));
+        vm.store(address(ZERO_EX_ADDRESS), slotId, bytes32(uint256(1)));
+    }
+
     modifier skipIf(bool condition) {
         if (!condition) {
             _;

test/integration/ZeroExPairTest.t.sol

@@ -54,6 +54,11 @@ abstract contract ZeroExPairTest is BasePairTest {
         otcOrder.maker = MAKER;
         otcOrderHash = ZERO_EX.getOtcOrderHash(otcOrder);
 
+        // Set up MAKER to also allow signatures from OTHER_MAKER
+        //     vm.startPrank(MAKER);
+        //     ZERO_EX.registerAllowedOrderSigner(OTHER_MAKER, true);
+        allowRegisteredSigner(MAKER, OTHER_MAKER);
+
         // MetaTransactionV2
         IZeroEx.BatchSellSubcall[] memory calls = new IZeroEx.BatchSellSubcall[](1);
         calls[0] = IZeroEx.BatchSellSubcall({
@@ -82,10 +87,21 @@ abstract contract ZeroExPairTest is BasePairTest {
     }
 
     function testZeroEx_otcOrder() public {
+        IZeroEx.OtcOrder memory _otcOrder = otcOrder;
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(MAKER_PRIVATE_KEY, otcOrderHash);
         vm.startPrank(FROM, FROM);
         snapStartName("zeroEx_otcOrder");
-        ZERO_EX.fillOtcOrder(otcOrder, IZeroEx.Signature(IZeroEx.SignatureType.EIP712, v, r, s), uint128(amount()));
+        ZERO_EX.fillOtcOrder(_otcOrder, IZeroEx.Signature(IZeroEx.SignatureType.EIP712, v, r, s), uint128(amount()));
+        snapEnd();
+    }
+
+    function testZeroEx_otcOrder_allowedSigner() public {
+        IZeroEx.OtcOrder memory _otcOrder = otcOrder;
+        // MAKER has already registered OTHER_MAKER as a signer
+        (uint8 v, bytes32 r, bytes32 s) = vm.sign(OTHER_MAKER_PRIVATE_KEY, otcOrderHash);
+        vm.startPrank(FROM, FROM);
+        snapStartName("zeroEx_otcOrder_allowedSigner");
+        ZERO_EX.fillOtcOrder(_otcOrder, IZeroEx.Signature(IZeroEx.SignatureType.EIP712, v, r, s), uint128(amount()));
         snapEnd();
     }
 

test/integration/vendor/IZeroEx.sol

@@ -198,6 +198,7 @@ interface IZeroEx {
 
     function getOtcOrderHash(IZeroEx.OtcOrder memory order) external view returns (bytes32 orderHash);
     function lastOtcTxOriginNonce(address txOrigin, uint64 nonceBucket) external view returns (uint128 lastNonce);
+    function registerAllowedOrderSigner(address signer, bool allowed) external;
 
     function getMetaTransactionV2Hash(IMetaTransactionsFeatureV2.MetaTransactionDataV2 calldata mtx)
         external