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DemoERC721.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.4;

import {ERC721} from "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol";
import {Counters} from "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Counters.sol";

/// @dev This contract is only used for testing purposes
contract MockERC721 is ERC721 {
    using Counters for Counters.Counter;
    Counters.Counter private _tokenIds;

    string _tokenBaseURI;

    constructor(string memory tokenName, string memory tokenSymbol)
        ERC721(tokenName, tokenSymbol)
    {}

    function mint(address to_) external returns (uint256) {
        uint256 currentTokenId = _tokenIds.current();
        _mint(to_, currentTokenId);
        _tokenIds.increment();
        return currentTokenId;
    }

    function setTokenBaseURI(string memory baseURI) external {
        _tokenBaseURI = baseURI;
    }

    function _baseURI() internal view virtual override returns (string memory) {
        return _tokenBaseURI;
    }
}