feat: add helper for fetching current implementation (#17)

src/ProxyHelpers.sol

@@ -1,15 +1,30 @@
 // SPDX-License-Identifier: AGPL-3.0
 pragma solidity >=0.7.5 <0.9.0;
 
-import "forge-std/Vm.sol";
+import 'forge-std/Vm.sol';
 
 library ProxyHelpers {
-    function getInitializableAdminUpgradeabilityProxyAdmin(Vm vm, address proxy) internal returns (address) {
-        address slot = address(
-            uint160(uint256(vm.load(
-                    proxy,
-                    0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103
-                ))));
-        return slot;
-    }
-}
+  function getInitializableAdminUpgradeabilityProxyAdmin(Vm vm, address proxy)
+    internal
+    returns (address)
+  {
+    address slot = address(
+      uint160(
+        uint256(vm.load(proxy, 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103))
+      )
+    );
+    return slot;
+  }
+
+  function getInitializableAdminUpgradeabilityProxyImplementation(Vm vm, address proxy)
+    internal
+    returns (address)
+  {
+    address slot = address(
+      uint160(
+        uint256(vm.load(proxy, 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc))
+      )
+    );
+    return slot;
+  }
+}

src/test/ProxyHelpers.t.sol

@@ -17,4 +17,12 @@ contract ProxyHelpersTest is Test {
     );
     assertEq(admin, GovHelpers.LONG_EXECUTOR);
   }
+
+  function testImplementation() public {
+    address implementation = ProxyHelpers.getInitializableAdminUpgradeabilityProxyImplementation(
+      vm,
+      0x41A08648C3766F9F9d85598fF102a08f4ef84F84
+    );
+    assertEq(implementation, 0xadC74A134082eA85105258407159FBB428a73782);
+  }
 }