chore: fix test

Author: ypatil12

src/test/mocks/OperatorTableUpdaterMock.sol

@@ -7,4 +7,15 @@ import "src/contracts/interfaces/IOperatorTableUpdater.sol";
 contract OperatorTableUpdaterMock is Test {
     receive() external payable {}
     fallback() external payable {}
+
+    mapping(uint32 referenceTimestamp => bool valid) internal _invalidRoots;
+
+    function isRootValidByTimestamp(uint32 referenceTimestamp) external view returns (bool) {
+        // If the root is invalid, return false
+        return !_invalidRoots[referenceTimestamp];
+    }
+
+    function invalidateRoot(uint32 referenceTimestamp) external {
+        _invalidRoots[referenceTimestamp] = true;
+    }
 }

src/test/unit/BN254CertificateVerifierUnit.t.sol

@@ -407,11 +407,7 @@ contract BN254CertificateVerifierUnitTests_verifyCertificate is BN254Certificate
         uint32 referenceTimestamp = _initializeOperatorTableBase();
 
         // Mock the operatorTableUpdater to return false for isRootValidByTimestamp
-        vm.mockCall(
-            address(operatorTableUpdaterMock),
-            abi.encodeWithSelector(IOperatorTableUpdater.isRootValidByTimestamp.selector, referenceTimestamp),
-            abi.encode(false)
-        );
+        operatorTableUpdaterMock.invalidateRoot(referenceTimestamp);
 
         BN254Certificate memory cert;
         cert.referenceTimestamp = referenceTimestamp;

src/test/unit/ECDSACertificateVerifierUnit.t.sol

@@ -381,12 +381,7 @@ contract ECDSACertificateVerifierUnitTests_verifyCertificate is ECDSACertificate
         // Initialize operator table with a valid root
         uint32 referenceTimestamp = _initializeOperatorTableBase();
 
-        // Mock the operatorTableUpdater to return false for isRootValidByTimestamp
-        vm.mockCall(
-            address(operatorTableUpdaterMock),
-            abi.encodeWithSelector(IOperatorTableUpdater.isRootValidByTimestamp.selector, referenceTimestamp),
-            abi.encode(false)
-        );
+        operatorTableUpdaterMock.invalidateRoot(referenceTimestamp);
 
         IECDSACertificateVerifierTypes.ECDSACertificate memory cert;
         cert.referenceTimestamp = referenceTimestamp;