chore: move the mock to another file

packages/contracts-bedrock/test/L2/SuperchainERC20.t.sol

@@ -18,20 +18,7 @@ import { BeaconProxy } from "@openzeppelin/contracts-v5/proxy/beacon/BeaconProxy
 // Target contract
 import { SuperchainERC20, ISuperchainERC20Extension } from "src/L2/SuperchainERC20.sol";
 import { ISuperchainERC20Errors } from "src/L2/interfaces/ISuperchainERC20.sol";
-
-contract SuperchainERC20Implementation is SuperchainERC20 {
-    /// @notice Semantic version.
-    /// @custom:semver 1.0.0-mock
-    string public constant override version = "1.0.0-mock";
-
-    function name() public pure override returns (string memory) {
-        return "SuperchainERC20";
-    }
-
-    function symbol() public pure override returns (string memory) {
-        return "SCE";
-    }
-}
+import { SuperchainERC20ImplementationMock } from "test/mocks/SuperchainERC20ImplementationMock.sol";
 
 /// @title SuperchainERC20Test
 /// @notice Contract for testing the SuperchainERC20 contract.
@@ -44,7 +31,7 @@ contract SuperchainERC20Test is Test {
 
     /// @notice Sets up the test suite.
     function setUp() public {
-        superchainERC20 = new SuperchainERC20Implementation();
+        superchainERC20 = new SuperchainERC20ImplementationMock();
     }
 
     /// @notice Helper function to setup a mock and expect a call to it.

packages/contracts-bedrock/test/mocks/SuperchainERC20ImplementationMock.sol

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.25;
+
+import { SuperchainERC20 } from "src/L2/SuperchainERC20.sol";
+
+/// @notice Mock contract just to create tests over an implementation of the SuperchainERC20 abstract contract.
+contract SuperchainERC20ImplementationMock is SuperchainERC20 {
+    /// @notice Semantic version.
+    /// @custom:semver 1.0.0-beta
+    string public constant override version = "1.0.0-beta";
+
+    function name() public pure override returns (string memory) {
+        return "SuperchainERC20";
+    }
+
+    function symbol() public pure override returns (string memory) {
+        return "SCE";
+    }
+}