test: add mock tokens

src/mocks/token/MockERC20.sol

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+
+contract MockERC20 is ERC20 {
+  constructor(string memory name, string memory symbol) ERC20(name, symbol) { }
+
+  function mint(address to, uint256 amount) external {
+    _mint(to, amount);
+  }
+}

src/mocks/token/MockWrapToken.sol

@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GNU
+pragma solidity ^0.8.0;
+
+/**
+ * @notice This contract MUST BE used in development only.
+ */
+contract MockWrapToken {
+  string public name;
+  string public symbol;
+  uint8 public decimals = 18;
+
+  event Approval(address indexed src, address indexed guy, uint256 wad);
+  event Transfer(address indexed src, address indexed dst, uint256 wad);
+  event Deposit(address indexed dst, uint256 wad);
+  event Withdrawal(address indexed src, uint256 wad);
+
+  mapping(address => uint256) public balanceOf;
+  mapping(address => mapping(address => uint256)) public allowance;
+
+  constructor(string memory name_, string memory symbol_) {
+    name = name_;
+    symbol = symbol_;
+  }
+
+  receive() external payable {
+    deposit();
+  }
+
+  fallback() external payable {
+    deposit();
+  }
+
+  function deposit() public payable {
+    balanceOf[msg.sender] += msg.value;
+    emit Deposit(msg.sender, msg.value);
+  }
+
+  function withdraw(uint256 wad) public {
+    require(balanceOf[msg.sender] >= wad);
+    balanceOf[msg.sender] -= wad;
+    payable(msg.sender).transfer(wad);
+    emit Withdrawal(msg.sender, wad);
+  }
+
+  function totalSupply() public view returns (uint256) {
+    return address(this).balance;
+  }
+
+  function approve(address guy, uint256 wad) public returns (bool) {
+    allowance[msg.sender][guy] = wad;
+    emit Approval(msg.sender, guy, wad);
+    return true;
+  }
+
+  function transfer(address dst, uint256 wad) public returns (bool) {
+    return transferFrom(msg.sender, dst, wad);
+  }
+
+  function transferFrom(address src, address dst, uint256 wad) public returns (bool) {
+    require(balanceOf[src] >= wad);
+
+    if (src != msg.sender && allowance[src][msg.sender] != type(uint256).max) {
+      require(allowance[src][msg.sender] >= wad);
+      allowance[src][msg.sender] -= wad;
+    }
+
+    balanceOf[src] -= wad;
+    balanceOf[dst] += wad;
+
+    emit Transfer(src, dst, wad);
+
+    return true;
+  }
+}