chore: coverage nits

src/crosschain-data/extensions/CoreStateRegistry.sol

@@ -789,9 +789,10 @@ contract CoreStateRegistry is BaseStateRegistry, ICoreStateRegistry {
         bool fulfilment;
         bool errors;
         for (uint256 i; i < numberOfVaults; ++i) {
-            /// @dev if updating the deposit payload fails because of slippage, multiVaultData.amounts[i] is set to 0
-            /// @dev this means that this amount was already added to the failedDeposits state variable and should not
-            /// be re-added (or processed here)
+            /// @dev it is not possible in theory to have multiVaultData.amounts to be 0 at this point
+            /// @dev this is due to the fact that 0 values are moved in updateDeposit which must always run prior to
+            /// processing the payload
+            /// @dev this check is added here only for sanity purposes and full coverage of the line is not possible
             if (multiVaultData.amounts[i] != 0) {
                 underlying = IERC20(_getVaultAsset(superforms[i]));
 

test/unit/crosschain-data/extensions/CoreStateRegistry.t.sol

@@ -99,6 +99,12 @@ contract CoreStateRegistryTest is ProtocolActions {
         vm.prank(deployer);
         vm.expectRevert(Error.BRIDGE_TOKENS_PENDING.selector);
         CoreStateRegistry(payable(getContract(AVAX, "CoreStateRegistry"))).processPayload{ value: nativeValue }(1);
+
+        vm.prank(deployer);
+        MockERC20(getContract(AVAX, "DAI")).transfer(getContract(AVAX, "CoreStateRegistry"), 838);
+
+        vm.prank(deployer);
+        CoreStateRegistry(payable(getContract(AVAX, "CoreStateRegistry"))).processPayload{ value: nativeValue }(1);
     }
 
     /// @dev this test ensures that if a superform update failed because of slippage in 2 of 4 vaults

test/unit/payments/PaymentHelper.t.sol

@@ -303,6 +303,89 @@ contract PaymentHelperTest is ProtocolActions {
         assertGt(fees, 0);
     }
 
+    function test_estimateSingleXChainMultiVault_retain4626() public {
+        uint8[] memory ambIds = new uint8[](1);
+
+        ambIds[0] = 1;
+        ambIds[0] = 2;
+
+        bytes memory emptyBytes;
+        uint256[] memory superFormIds = new uint256[](1);
+        superFormIds[0] = _generateTimelockSuperformPackWithShift();
+
+        uint256[] memory uint256MemoryArray = new uint256[](1);
+        uint256MemoryArray[0] = 420;
+
+        LiqRequest[] memory liqRequestMemoryArray = new LiqRequest[](1);
+        liqRequestMemoryArray[0] = LiqRequest(emptyBytes, address(0), address(0), 1, ETH, 420);
+        bool[] memory retain4626 = new bool[](1);
+
+        retain4626[0] = true;
+
+        (,,, uint256 fees) = paymentHelper.estimateSingleXChainMultiVault(
+            SingleXChainMultiVaultStateReq(
+                ambIds,
+                ARBI,
+                MultiVaultSFData(
+                    superFormIds,
+                    /// timelock
+                    uint256MemoryArray,
+                    uint256MemoryArray,
+                    uint256MemoryArray,
+                    liqRequestMemoryArray,
+                    emptyBytes,
+                    new bool[](1),
+                    retain4626,
+                    receiverAddress,
+                    receiverAddress,
+                    emptyBytes
+                )
+            ),
+            false
+        );
+        assertGt(fees, 0);
+    }
+
+    function test_estimateSingleXChainMultiVault_sameDst_deposit() public {
+        uint8[] memory ambIds = new uint8[](1);
+
+        ambIds[0] = 1;
+        ambIds[0] = 2;
+
+        bytes memory emptyBytes;
+        uint256[] memory superFormIds = new uint256[](1);
+        superFormIds[0] = _generateTimelockSuperformPackWithShift();
+
+        uint256[] memory uint256MemoryArray = new uint256[](1);
+        uint256MemoryArray[0] = 420;
+
+        LiqRequest[] memory liqRequestMemoryArray = new LiqRequest[](1);
+        liqRequestMemoryArray[0] = LiqRequest(emptyBytes, address(0), address(0), 1, ETH, 420);
+
+        (,,, uint256 fees) = paymentHelper.estimateSingleXChainMultiVault(
+            SingleXChainMultiVaultStateReq(
+                ambIds,
+                ETH,
+                MultiVaultSFData(
+                    superFormIds,
+                    /// timelock
+                    uint256MemoryArray,
+                    uint256MemoryArray,
+                    uint256MemoryArray,
+                    liqRequestMemoryArray,
+                    emptyBytes,
+                    new bool[](1),
+                    new bool[](1),
+                    receiverAddress,
+                    receiverAddress,
+                    emptyBytes
+                )
+            ),
+            true
+        );
+        assertGt(fees, 0);
+    }
+
     function test_estimateMultiDstSingleVault_formImplPaused() public {
         vm.prank(deployer);
         SuperformFactory(getContract(ETH, "SuperformFactory")).changeFormImplementationPauseStatus(