unit tests

contracts/prototypes/zevm/GatewayZEVM.sol

@@ -62,7 +62,6 @@ contract GatewayZEVM is Initializable, OwnableUpgradeable, UUPSUpgradeable {
         emit Call(msg.sender, receiver, message);
     }
 
-
     // Deposit foreign coins into ZRC20
     function deposit(
         address zrc20,

contracts/prototypes/zevm/TestZContract.sol

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.7;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "../../zevm/interfaces/zContract.sol";
+
+contract TestZContract is zContract {
+    event ContextData(bytes origin, address sender, uint256 chainID, address msgSender, string message);
+
+    function onCrossChainCall(
+        zContext calldata context,
+        address zrc20,
+        uint256 amount,
+        bytes calldata message
+    ) external override {
+        string memory decodedMessage = abi.decode(message, (string));
+        emit ContextData(context.origin, context.sender, context.chainID, msg.sender, decodedMessage);
+    }
+}

contracts/zevm/ZRC20.sol

@@ -26,6 +26,8 @@ contract ZRC20 is IZRC20, IZRC20Metadata, ZRC20Errors {
     CoinType public immutable COIN_TYPE;
     /// @notice System contract address.
     address public SYSTEM_CONTRACT_ADDRESS;
+     /// @notice Gateway contract address.
+    address public GATEWAY_CONTRACT_ADDRESS;
     /// @notice Gas limit.
     uint256 public GAS_LIMIT;
     /// @notice Protocol flat fee.
@@ -76,6 +78,11 @@ contract ZRC20 is IZRC20, IZRC20Metadata, ZRC20Errors {
         SYSTEM_CONTRACT_ADDRESS = systemContractAddress_;
     }
 
+    // TODO: discuss
+    function setGatewayContractAddress(address gateway) external {
+        GATEWAY_CONTRACT_ADDRESS = gateway;
+    }
+
     /**
      * @dev ZRC20 name
      * @return name as string
@@ -223,7 +230,7 @@ contract ZRC20 is IZRC20, IZRC20Metadata, ZRC20Errors {
      * @return true/false if succeeded/failed.
      */
     function deposit(address to, uint256 amount) external override returns (bool) {
-        if (msg.sender != FUNGIBLE_MODULE_ADDRESS && msg.sender != SYSTEM_CONTRACT_ADDRESS) revert InvalidSender();
+        if (msg.sender != FUNGIBLE_MODULE_ADDRESS && msg.sender != SYSTEM_CONTRACT_ADDRESS && msg.sender != GATEWAY_CONTRACT_ADDRESS) revert InvalidSender();
         _mint(to, amount);
         emit Deposit(abi.encodePacked(FUNGIBLE_MODULE_ADDRESS), to, amount);
         return true;

contracts/zevm/interfaces/IZRC20.sol

@@ -28,6 +28,8 @@ interface IZRC20 {
 
     function PROTOCOL_FLAT_FEE() external view returns (uint256);
 
+    function setGatewayContractAddress(address gateway) external;
+
     event Transfer(address indexed from, address indexed to, uint256 value);
     event Approval(address indexed owner, address indexed spender, uint256 value);
     event Deposit(bytes from, address indexed to, uint256 value);