Add functions with mutex to ReentrantERC20Token and update IExchange with missing function

contracts/exchange/contracts/src/interfaces/ISignatureValidator.sol

@@ -39,6 +39,16 @@ contract ISignatureValidator {
     )
         external;
 
+    /// @dev Approves/unnapproves an OrderValidator contract to verify signatures on signer's behalf
+    ///      using the `OrderValidator` signature type.
+    /// @param validatorAddress Address of Validator contract.
+    /// @param approval Approval or disapproval of  Validator contract.
+    function setOrderValidatorApproval(
+        address validatorAddress,
+        bool approval
+    )
+        external;
+
     /// @dev Verifies that a signature for a hash is valid.
     /// @param hash Message hash that is signed.
     /// @param signerAddress Address of signer.

contracts/exchange/contracts/test/ReentrantERC20Token.sol

@@ -50,7 +50,9 @@ contract ReentrantERC20Token is
         CANCEL_ORDER,
         BATCH_CANCEL_ORDERS,
         CANCEL_ORDERS_UP_TO,
+        PRE_SIGN,
         SET_SIGNATURE_VALIDATOR_APPROVAL,
+        SET_ORDER_VALIDATOR_APPROVAL,
         NONE
     }
 
@@ -161,12 +163,23 @@ contract ReentrantERC20Token is
                 exchange.cancelOrdersUpTo.selector,
                 1
             );
+        } else if (currentFunctionId == uint8(ExchangeFunction.PRE_SIGN)) {
+            callData = abi.encodeWithSelector(
+                exchange.preSign.selector,
+                uint256(getRandomAddress())
+            );
         } else if (currentFunctionId == uint8(ExchangeFunction.SET_SIGNATURE_VALIDATOR_APPROVAL)) {
             callData = abi.encodeWithSelector(
                 exchange.setSignatureValidatorApproval.selector,
                 getRandomAddress(),
                 false
             );
+        } else if (currentFunctionId == uint8(ExchangeFunction.SET_ORDER_VALIDATOR_APPROVAL)) {
+            callData = abi.encodeWithSelector(
+                exchange.setOrderValidatorApproval.selector,
+                getRandomAddress(),
+                false
+            );
         } else {
             return true;
         }