test: coverage for SuccinctFeeVault

contracts/src/payments/SuccinctFeeVault.sol

@@ -25,17 +25,6 @@ contract SuccinctFeeVault is IFeeVault, TimelockedUpgradeable {
     /// @notice The allowed senders for the deduct functions.
     mapping(address => bool) public allowedDeductors;
 
-    event Received(address indexed account, address indexed token, uint256 amount);
-    event Deducted(address indexed account, address indexed token, uint256 amount);
-    event Collected(address indexed to, address indexed token, uint256 amount);
-
-    error InvalidAccount(address account);
-    error InvalidToken(address token);
-    error InsufficentAllowance(address token, uint256 amount);
-    error InsufficientBalance(address token, uint256 amount);
-    error FailedToSendNative(uint256 amount);
-    error OnlyDeductor(address sender);
-
     modifier onlyDeductor() {
         if (!allowedDeductors[msg.sender]) {
             revert OnlyDeductor(msg.sender);
@@ -168,4 +157,8 @@ contract SuccinctFeeVault is IFeeVault, TimelockedUpgradeable {
 
         emit Collected(_to, _token, _amount);
     }
+
+    /// @dev This empty reserved space to add new variables without shifting down storage.
+    ///      See: https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
+    uint256[50] private __gap;
 }

contracts/src/payments/interfaces/IFeeVault.sol

@@ -1,22 +1,23 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.16;
 
-interface IFeeVault {
-    /// @notice Returns the amount of active balance that an account has.
-    /// @param token The address of the token to check the balance of. To check native currency
-    ///        balance, use address(0) as the token address.
-    /// @param account The address of the account to check the balance of.
-    function balances(address token, address account) external view returns (uint256);
+interface IFeeVaultEvents {
+    event Received(address indexed account, address indexed token, uint256 amount);
+    event Deducted(address indexed account, address indexed token, uint256 amount);
+    event Collected(address indexed to, address indexed token, uint256 amount);
+}
 
-    /// @notice Deposit the specified amount of native currency from the caller.
-    /// @dev The native currency is represented by address(0) in balances.
-    /// @param account The account to deposit the native currency for.
-    function depositNative(address account) external payable;
+interface IFeeVaultErrors {
+    error InvalidAccount(address account);
+    error InvalidToken(address token);
+    error InsufficentAllowance(address token, uint256 amount);
+    error InsufficientBalance(address token, uint256 amount);
+    error FailedToSendNative(uint256 amount);
+    error OnlyDeductor(address sender);
+}
 
-    /// @notice Deposit the specified amount of the specified token from the caller.
-    /// @dev MUST approve this contract to spend at least `amount` of `token` before calling this.
-    /// @param account The account to deposit the tokens to.
-    /// @param token The address of the token to deposit.
-    /// @param amount The amount of the token to deposit.
+interface IFeeVault is IFeeVaultEvents, IFeeVaultErrors {
+    function balances(address token, address account) external view returns (uint256);
+    function depositNative(address account) external payable;
     function deposit(address account, address token, uint256 amount) external;
 }