postop cost added back and more tests added

contracts/common/Errors.sol

@@ -66,4 +66,9 @@ contract BiconomySponsorshipPaymasterErrors {
      * @notice Throws when trying to withdraw to address(0)
      */
     error CanNotWithdrawToZeroAddress();
+
+    /**
+     * @notice Throws when trying postOpCost is too high
+     */
+    error PostOpCostTooHigh();
 }

contracts/sponsorship/SponsorshipPaymasterWithPremium.sol

@@ -39,6 +39,7 @@ contract BiconomySponsorshipPaymaster is
 
     address public verifyingSigner;
     address public feeCollector;
+    uint48 public postOpCost;
     uint32 private constant PRICE_DENOMINATOR = 1e6;
 
     // note: could rename to PAYMASTER_ID_OFFSET
@@ -119,6 +120,20 @@ contract BiconomySponsorshipPaymaster is
         emit FeeCollectorChanged(oldFeeCollector, _newFeeCollector, msg.sender);
     }
 
+    /**
+     * @dev Set a new unaccountedEPGasOverhead value.
+     * @param value The new value to be set as the unaccountedEPGasOverhead.
+     * @notice only to be called by the owner of the contract.
+     */
+    function setPostopCost(uint48 value) external payable onlyOwner {
+        if (value > 200_000) {
+            revert PostOpCostTooHigh();
+        }
+        uint256 oldValue = postOpCost;
+        postOpCost = value;
+        emit PostopCostChanged(oldValue, value);
+    }
+
     /**
      * @dev Override the default implementation.
      */
@@ -232,12 +247,21 @@ contract BiconomySponsorshipPaymaster is
     /// @dev This function is called after a user operation has been executed or reverted.
     /// @param context The context containing the token amount and user sender address.
     /// @param actualGasCost The actual gas cost of the transaction.
-    function _postOp(PostOpMode, bytes calldata context, uint256 actualGasCost, uint256) internal override {
+    function _postOp(
+        PostOpMode,
+        bytes calldata context,
+        uint256 actualGasCost,
+        uint256 actualUserOpFeePerGas
+    )
+        internal
+        override
+    {
         unchecked {
             (address paymasterId, uint32 dynamicAdjustment, bytes32 userOpHash) =
                 abi.decode(context, (address, uint32, bytes32));
 
-            uint256 adjustedGasCost = (actualGasCost * dynamicAdjustment) / PRICE_DENOMINATOR;
+            uint256 totalGasCost = actualGasCost + (postOpCost * actualUserOpFeePerGas);
+            uint256 adjustedGasCost = (totalGasCost * dynamicAdjustment) / PRICE_DENOMINATOR;
 
             // Deduct the adjusted cost
             paymasterIdBalances[paymasterId] -= adjustedGasCost;

test/foundry/base/NexusTestBase.sol

@@ -477,6 +477,8 @@ abstract contract NexusTestBase is CheatCodes, BaseEventsAndErrors {
             //premium
             expectedPremium = totalGasFeesCharged - ((totalGasFeesCharged * 1e6) / premium);
             actualPremium = resultingFeeCollectorPaymasterBalance - initialFeeCollectorBalance;
-        } else revert("Premium must be more than 1e6");
+        } else {
+            revert("Premium must be more than 1e6");
+        }
     }
 }

test/foundry/unit/concrete/TestSponsorshipPaymasterWithPremiumTest.t.sol

@@ -106,6 +106,24 @@ contract TestSponsorshipPaymasterWithPremium is NexusTestBase {
         bicoPaymaster.setFeeCollector(DAN_ADDRESS);
     }
 
+    function test_SetPostopCost() external prankModifier(PAYMASTER_OWNER.addr) {
+        uint48 initialPostopCost = bicoPaymaster.postOpCost();
+        uint48 newPostopCost = 5_000;
+
+        vm.expectEmit(true, true, false, true, address(bicoPaymaster));
+        emit IBiconomySponsorshipPaymaster.PostopCostChanged(initialPostopCost, newPostopCost);
+        bicoPaymaster.setPostopCost(newPostopCost);
+
+        uint48 resultingPostopCost = bicoPaymaster.postOpCost();
+        assertEq(resultingPostopCost, newPostopCost);
+    }
+
+    function test_RevertIf_SetPostopCostToHigh() external prankModifier(PAYMASTER_OWNER.addr) {
+        uint48 newPostopCost = 200_001;
+        vm.expectRevert(abi.encodeWithSelector(PostOpCostTooHigh.selector));
+        bicoPaymaster.setPostopCost(newPostopCost);
+    }
+
     function test_DepositFor() external {
         uint256 dappPaymasterBalance = bicoPaymaster.getBalance(DAPP_ACCOUNT.addr);
         uint256 depositAmount = 10 ether;
@@ -134,6 +152,31 @@ contract TestSponsorshipPaymasterWithPremium is NexusTestBase {
         bicoPaymaster.deposit{ value: 1 ether }();
     }
 
+    function test_WithdrawTo() external prankModifier(DAPP_ACCOUNT.addr) {
+        uint256 depositAmount = 10 ether;
+        bicoPaymaster.depositFor{ value: depositAmount }(DAPP_ACCOUNT.addr);
+        uint256 danInitialBalance = DAN_ADDRESS.balance;
+
+        vm.expectEmit(true, true, true, true, address(bicoPaymaster));
+        emit IBiconomySponsorshipPaymaster.GasWithdrawn(DAPP_ACCOUNT.addr, DAN_ADDRESS, depositAmount);
+        bicoPaymaster.withdrawTo(payable(DAN_ADDRESS), depositAmount);
+
+        uint256 dappPaymasterBalance = bicoPaymaster.getBalance(DAPP_ACCOUNT.addr);
+        assertEq(dappPaymasterBalance, 0 ether);
+        uint256 expectedDanBalance = danInitialBalance + depositAmount;
+        assertEq(DAN_ADDRESS.balance, expectedDanBalance);
+    }
+
+    function test_RevertIf_WithdrawToZeroAddress() external prankModifier(DAPP_ACCOUNT.addr) {
+        vm.expectRevert(abi.encodeWithSelector(CanNotWithdrawToZeroAddress.selector));
+        bicoPaymaster.withdrawTo(payable(address(0)), 0 ether);
+    }
+
+    function test_RevertIf_WithdrawToExceedsBalance() external prankModifier(DAPP_ACCOUNT.addr) {
+        vm.expectRevert(abi.encodeWithSelector(InsufficientFundsInGasTank.selector));
+        bicoPaymaster.withdrawTo(payable(DAN_ADDRESS), 1 ether);
+    }
+
     function test_ValidatePaymasterAndPostOpWithoutPremium() external prankModifier(DAPP_ACCOUNT.addr) {
         bicoPaymaster.depositFor{ value: 10 ether }(DAPP_ACCOUNT.addr);
         // No premoium