ERC721被创建为空地址。

Question

下面是薄荷ERC721令牌的合同代码：

contract NFT is ERC721URIStorage, Ownable {

    mapping(uint256 => address) private _owners;
    mapping(address => uint256) private _balances;

    constructor()ERC721 ("Lambo", "LMB") public {}

    function mintNFT(address to, uint256 tokenId, string memory tokenURI) public {
        require(to != address(0), "ERC721: token mint to contract owner address");
        require(!_exists(tokenId), "ERC721: token already minted");
        _mint(to, tokenId);
        _setTokenURI(tokenId, tokenURI);
    }

    function burnToken(uint256 tokenId) public {
        _burn(tokenId);
    }

    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for zero address");
        return _balances[owner];
    }

    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        return owner;
    }
}

为薄荷ERC721令牌编写测试，并验证造币地址是否拥有令牌：

const firstMinter = accounts[4]; //0xD235287FcBE172407F5692Bc25cD73989a7d6777

it("Minting ERC721 Tokens", async() => {
        let nftInstance = await mintNFTs.deployed();

        await nftInstance.mintNFT(firstMinter, 1, "ipfs://QmQZTUekV9P7cKRiVVwdahyaFNZEt6Yt7fGtcRfsLSWpyP/evocube.json");

        console.log("ERC721 Tokens have been minted for whitelist")
    })

    it("Verifying Whitelist Owners have ERC721 Tokens", async() => {

        const nftInstance = await mintNFTs.deployed();

        let firstOwner = await nftInstance.ownerOf(1);
        console.log(firstOwner);
        assert.equal(firstMinter, firstOwner, "Error: First Minter doesn't own the token");
    })

以下是我所收到的测试结果：

AssertionError: Error: First不拥有令牌:预期'0xD235287FcBE172407F5692Bc25cD73989a7d6777‘等于’0x00000000000000000000000000000000000000000‘。

Answer 1

我认为您的问题在于，firstMinter在部署tokenID 1之前还没有拥有NFT，所以firstOwner是空的。

assert.equal(firstMinter, firstOwner, "Error: First Minter doesn't own the token");