diff --git a/test/harnesses/token/ERC20/ERC20/ERC20TransferFacetHarness.sol b/test/harnesses/token/ERC20/ERC20/ERC20TransferFacetHarness.sol
deleted file mode 100644
index 83c2d177..00000000
--- a/test/harnesses/token/ERC20/ERC20/ERC20TransferFacetHarness.sol
+++ /dev/null
@@ -1,30 +0,0 @@
-// SPDX-License-Identifier: MIT
-pragma solidity >=0.8.30;
-
-/* Compose
- * https://compose.diamonds
- */
-
-import {ERC20TransferFacet} from "src/token/ERC20/ERC20/ERC20TransferFacet.sol";
-
-/**
- * @title ERC20TransferFacetHarness
- * @notice Test harness for ERC20TransferFacet that adds minting for testing
- */
-contract ERC20TransferFacetHarness is ERC20TransferFacet {
-    /**
-     * @notice Mint tokens to an address
-     * @dev Only used for testing - exposes internal mint functionality
-     */
-    function mint(address _to, uint256 _value) external {
-        ERC20TransferStorage storage s = getStorage();
-        if (_to == address(0)) {
-            revert ERC20InvalidReceiver(address(0));
-        }
-        unchecked {
-            s.totalSupply += _value;
-            s.balanceOf[_to] += _value;
-        }
-        emit Transfer(address(0), _to, _value);
-    }
-}
diff --git a/test/token/ERC20/ERC20/ERC20BurnFacet.t.sol b/test/token/ERC20/ERC20/ERC20BurnFacet.t.sol
index 1ca6cc40..c28ebb35 100644
--- a/test/token/ERC20/ERC20/ERC20BurnFacet.t.sol
+++ b/test/token/ERC20/ERC20/ERC20BurnFacet.t.sol
@@ -7,7 +7,7 @@ pragma solidity >=0.8.30;
 
 import {Test} from "forge-std/Test.sol";
 import {ERC20BurnFacet} from "src/token/ERC20/ERC20/ERC20BurnFacet.sol";
-import {ERC20BurnFacetHarness} from "test/harnesses/token/ERC20/ERC20/ERC20BurnFacetHarness.sol";
+import {ERC20BurnFacetHarness} from "./harnesses/ERC20BurnFacetHarness.sol";
 
 contract ERC20BurnFacetTest is Test {
     ERC20BurnFacetHarness public token;
diff --git a/test/token/ERC20/ERC20/ERC20PermitFacet.t.sol b/test/token/ERC20/ERC20/ERC20PermitFacet.t.sol
index 66d116fe..cdf6e98e 100644
--- a/test/token/ERC20/ERC20/ERC20PermitFacet.t.sol
+++ b/test/token/ERC20/ERC20/ERC20PermitFacet.t.sol
@@ -7,7 +7,7 @@ pragma solidity >=0.8.30;
 
 import {Test} from "forge-std/Test.sol";
 import {ERC20PermitFacet} from "src/token/ERC20/ERC20Permit/ERC20PermitFacet.sol";
-import {ERC20PermitFacetHarness} from "test/harnesses/token/ERC20/ERC20/ERC20PermitFacetHarness.sol";
+import {ERC20PermitFacetHarness} from "./harnesses/ERC20PermitFacetHarness.sol";
 
 contract ERC20BurnFacetTest is Test {
     ERC20PermitFacetHarness public token;
diff --git a/test/harnesses/token/ERC20/ERC20/ERC20BurnFacetHarness.sol b/test/token/ERC20/ERC20/harnesses/ERC20BurnFacetHarness.sol
similarity index 100%
rename from test/harnesses/token/ERC20/ERC20/ERC20BurnFacetHarness.sol
rename to test/token/ERC20/ERC20/harnesses/ERC20BurnFacetHarness.sol
diff --git a/test/harnesses/token/ERC20/ERC20/ERC20PermitFacetHarness.sol b/test/token/ERC20/ERC20/harnesses/ERC20PermitFacetHarness.sol
similarity index 100%
rename from test/harnesses/token/ERC20/ERC20/ERC20PermitFacetHarness.sol
rename to test/token/ERC20/ERC20/harnesses/ERC20PermitFacetHarness.sol
diff --git a/test/utils/storage/ERC20StorageUtils.sol b/test/utils/storage/ERC20StorageUtils.sol
new file mode 100644
index 00000000..630642a6
--- /dev/null
+++ b/test/utils/storage/ERC20StorageUtils.sol
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+import {Vm} from "forge-std/Vm.sol";
+
+/**
+ * @title ERC20StorageUtils
+ * @notice Storage manipulation utilities for ERC20 token testing
+ * @dev Uses vm.load and vm.store to directly manipulate storage slots
+ */
+library ERC20StorageUtils {
+    Vm private constant vm = Vm(address(uint160(uint256(keccak256("hevm cheat code")))));
+
+    bytes32 internal constant ERC20_TRANSFER_STORAGE_POSITION = keccak256("compose.erc20.transfer");
+
+    /*//////////////////////////////////////////////////////////////
+                                GETTERS
+    //////////////////////////////////////////////////////////////*/
+
+    /*
+     * @notice ERC-20 Transfer storage layout (ERC-8042 standard)
+     * @custom:storage-location erc8042:compose.erc20.transfer
+     *
+     * Slot 0: mapping(address owner => uint256 balance) balanceOf
+     * Slot 1: uint256 totalSupply
+     * Slot 2: mapping(address owner => mapping(address spender => uint256)) allowance
+     */
+
+    function balanceOf(address target, address owner) internal view returns (uint256) {
+        bytes32 slot = keccak256(abi.encode(owner, uint256(ERC20_TRANSFER_STORAGE_POSITION)));
+        return uint256(vm.load(target, slot));
+    }
+
+    function totalSupply(address target) internal view returns (uint256) {
+        bytes32 slot = bytes32(uint256(ERC20_TRANSFER_STORAGE_POSITION) + 1);
+        return uint256(vm.load(target, slot));
+    }
+
+    function allowance(address target, address owner, address spender) internal view returns (uint256) {
+        bytes32 ownerSlot = keccak256(abi.encode(owner, uint256(ERC20_TRANSFER_STORAGE_POSITION) + 2));
+        bytes32 slot = keccak256(abi.encode(spender, ownerSlot));
+        return uint256(vm.load(target, slot));
+    }
+
+    /*//////////////////////////////////////////////////////////////
+                                SETTERS
+    //////////////////////////////////////////////////////////////*/
+
+    function setBalance(address target, address owner, uint256 balance) internal {
+        bytes32 slot = keccak256(abi.encode(owner, uint256(ERC20_TRANSFER_STORAGE_POSITION)));
+        vm.store(target, slot, bytes32(balance));
+    }
+
+    function setTotalSupply(address target, uint256 supply) internal {
+        bytes32 slot = bytes32(uint256(ERC20_TRANSFER_STORAGE_POSITION) + 1);
+        vm.store(target, slot, bytes32(supply));
+    }
+
+    function setAllowance(address target, address owner, address spender, uint256 amount) internal {
+        bytes32 ownerSlot = keccak256(abi.encode(owner, uint256(ERC20_TRANSFER_STORAGE_POSITION) + 2));
+        bytes32 slot = keccak256(abi.encode(spender, ownerSlot));
+        vm.store(target, slot, bytes32(amount));
+    }
+
+    /**
+     * @notice Mint tokens by updating balance and totalSupply
+     */
+    function mint(address target, address to, uint256 amount) internal {
+        uint256 currentBalance = balanceOf(target, to);
+        uint256 currentSupply = totalSupply(target);
+
+        setBalance(target, to, currentBalance + amount);
+        setTotalSupply(target, currentSupply + amount);
+    }
+}