tests: add decimals tests

test/fuzz/MultiBlockHarvester.t.sol

@@ -13,6 +13,7 @@ import "../utils/FunctionUtils.sol";
 
 import "contracts/savings/Savings.sol";
 import "../mock/MockTokenPermit.sol";
+import "../mock/MockScaleDecimals.sol";
 import "contracts/helpers/MultiBlockHarvester.sol";
 
 import "contracts/transmuter/Storage.sol";
@@ -330,6 +331,22 @@ contract MultiBlockHarvestertTest is Fixture, FunctionUtils {
         assertEq(currentTargetExposure, targetExposure + 1);
     }
 
+    function test_ScaleDecimals() public {
+        MockScaleDecimals decimals = new MockScaleDecimals(1e8, accessControlManager, agToken, transmuter);
+
+        uint256 amount = decimals.scaleDecimals(18, 20, 1e18, true);
+        assertEq(amount, 1e20);
+
+        amount = decimals.scaleDecimals(20, 18, 1e18, false);
+        assertEq(amount, 1e20);
+
+        amount = decimals.scaleDecimals(18, 20, 1e18, false);
+        assertEq(amount, 1e16);
+
+        amount = decimals.scaleDecimals(20, 18, 1e18, true);
+        assertEq(amount, 1e16);
+    }
+
     function test_harvest_IncreaseExposureXEVT(uint256 amount) external {
         amount = 7022;
         _loadReserve(EURC, amount);

test/mock/MockScaleDecimals.sol

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: Unlicensed
+pragma solidity ^0.8.19;
+
+import "contracts/helpers/BaseHarvester.sol";
+
+contract MockScaleDecimals is BaseHarvester {
+    constructor(
+        uint96 initialMaxSlippage,
+        IAccessControlManager definitiveAccessControlManager,
+        IAgToken definitiveAgToken,
+        ITransmuter definitiveTransmuter
+    ) BaseHarvester(initialMaxSlippage, definitiveAccessControlManager, definitiveAgToken, definitiveTransmuter) {}
+
+    function harvest(address yieldBearingAsset, uint256 scale, bytes calldata extraData) external override {}
+
+    function scaleDecimals(
+        uint256 decimalsTokenIn,
+        uint256 decimalsTokenOut,
+        uint256 amountIn,
+        bool assetIn
+    ) external pure returns (uint256) {
+        return _scaleAmountBasedOnDecimals(decimalsTokenIn, decimalsTokenOut, amountIn, assetIn);
+    }
+}