add basic functional solidity test case

solidity/src/test/ExampleERC20.sol

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.17;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Permit.sol";
+
+contract ExampleERC20 is ERC20, ERC20Burnable, Ownable, ERC20Permit {
+    constructor() ERC20("NAME", "SYMBOL") Ownable(msg.sender) ERC20Permit("NAME") {}
+
+    function mint(address to, uint256 amount) public onlyOwner {
+        _mint(to, amount);
+    }
+}

solidity/test/MaybeMintERC721.t.sol

@@ -0,0 +1,42 @@
+pragma solidity 0.8.24;
+
+import {Test} from "forge-std/Test.sol";
+import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
+import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
+import {MaybeMintERC721} from "../src/MaybeMintERC721.sol";
+import {ExampleERC20} from "../src/test/ExampleERC20.sol";
+
+contract MaybeMintERC721Test is Test {
+    // Contracts
+    MaybeMintERC721 private erc721;
+    ExampleERC20 private erc20;
+
+    // MaybeMintERC721 parameters
+    address payable beneficiary = payable(address(100));
+    uint256 internal mintCost = 1 ether;
+    string internal name = "Maybe Mint ERC721 Test";
+    string internal symbol = "MAYBE";
+
+    // Test values
+    address payable internal user = payable(address(101));
+
+    function setUp() public virtual {
+        vm.deal(user, 10 ether);
+
+        erc20 = new ExampleERC20();
+        erc721 = new MaybeMintERC721(name, symbol, address(erc20), mintCost, beneficiary);
+    }
+
+    function test_mint() public {
+        erc20.mint(user, mintCost); // mint ERC20 to user
+
+        vm.prank(user);
+        erc20.approve(address(erc721), mintCost); // approve the ERC20 to be spent by MaybeMintERC721
+
+        vm.prank(user);
+        erc721.mint(); // mint ERC721 to user
+
+        assertEq(erc721.ownerOf(1), user); // user should own the ERC721 token
+    }
+}