Updateable oracle address

src/GEMxToken.sol

@@ -96,6 +96,10 @@ contract GEMxToken is
         return address(oracle);
     }
 
+    function setOracleAddress(address newAddress) external onlyRole(DEFAULT_ADMIN_ROLE) {
+        oracle = AggregatorV3Interface(newAddress);
+    }
+
     function getEsuPerToken() external view returns (uint256, uint256) {
         return (esuPerTokenValue, esuPerTokenPrecision);
     }

test/mocks/MockV3Aggregator.sol

@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: UNLICENSED
-
 pragma solidity 0.8.20;
 
 import {AggregatorV3Interface} from "@chainlink/contracts/v0.8/shared/interfaces/AggregatorV3Interface.sol";

test/unit/GEMxTokenTest.t.sol

@@ -59,6 +59,26 @@ contract GEMxTokenTest is Test {
         assertEq(esuPrecision, 100, "Initial EsuPerToken is 0.01");
     }
 
+    /*##################################################################################*/
+    /*################################# Oracle Update ##################################*/
+    /*##################################################################################*/
+
+    function testOnlyAdminCanUpdateOracle() public {
+        address currentOracleAddress = token.getOracleAddress();
+        MockV3Aggregator newOracle = new MockV3Aggregator(1000);
+
+        vm.expectRevert(
+            abi.encodeWithSelector(IAccessControl.AccessControlUnauthorizedAccount.selector, user, token.DEFAULT_ADMIN_ROLE())
+        );
+        vm.prank(user);
+        token.setOracleAddress(address(newOracle));
+        assertEq(token.getOracleAddress(), currentOracleAddress);
+
+        vm.prank(admin);
+        token.setOracleAddress(address(newOracle));
+        assertEq(token.getOracleAddress(), address(newOracle));
+    }
+
     /*##################################################################################*/
     /*###################################### ESU #######################################*/
     /*##################################################################################*/
@@ -132,7 +152,6 @@ contract GEMxTokenTest is Test {
         token.setEsuPerToken(9, 10000);
 
         (esu, esuPrecision) = token.getEsuPerToken();
-
         assertEq(esu, 9);
         assertEq(esuPrecision, 10000);
     }