CrossDomainMessenger: ensure the base gas is always large enough

packages/contracts-bedrock/contracts/test/CrossDomainMessenger.t.sol

@@ -22,6 +22,22 @@ contract CrossDomainMessenger_BaseGas_Test is Messenger_Initializer {
     function testFuzz_baseGas_succeeds(uint32 _minGasLimit) external view {
         L1Messenger.baseGas(hex"ff", _minGasLimit);
     }
+
+    /**
+     * @notice The baseGas function should always return a value greater than
+     *         or equal to the minimum gas limit value on the OptimismPortal.
+     *         This guarantees that the messengers will always pass sufficient
+     *         gas to the OptimismPortal.
+     */
+    function testFuzz_baseGas_portalMinGasLimit_succeeds(
+        bytes memory _data,
+        uint32 _minGasLimit
+    ) external {
+        vm.assume(_data.length <= type(uint64).max);
+        uint64 baseGas = L1Messenger.baseGas(_data, _minGasLimit);
+        uint64 minGasLimit = op.minimumGasLimit(uint64(_data.length));
+        assertTrue(baseGas >= minGasLimit);
+    }
 }
 
 /**