调整挖掘区块难度的AdjustDifficulty（...）函数未能通过测试用例来提高区块的难度（Node.js）

Question

我正在从头开始进行区块链项目，似乎在我的 adjustDifficulty（...）函数遇到问题。在测试中，用于正确提高块的挖掘难度的测试用例将失败。尽管难度调整似乎在应用程序运行时有效，但在测试中仍然失败。该函数位于Block.js文件的底部，并具有相应的笑话测试。任何帮助都将不胜感激！

p.s。我知道将GENESIS设置为Date.now（）会破坏对等2对等并进行同步。只是忽略它。

Block.js：

const SHA256 = require('crypto-js/sha256');

const { DIFFICULTY, MINE_RATE, GENESIS} = require('../config');

class Block {
    constructor (timestamp, lastHash, hash, data, nonce, difficulty) {
        this.timestamp = timestamp;
        this.lastHash = lastHash;
        this.hash = hash;
        this.data = data;
        this.nonce = nonce;
        this.difficulty = difficulty || DIFFICULTY;
    }

    toString() { // diagonal ticks, template string
        return `Block - 
                Timestamp : ${this.timestamp}
                Last Hash : ${this.lastHash.substring(1, 10)}
                Hash      : ${this.hash.substring(0, 10)}
                Nonce     : ${this.nonce}
                Difficulty: ${this.difficulty}
                Data      : ${this.data}`;
    }

    static genesis() { // creates genesis (origin) block
        return new this(GENESIS, '-----', 'f1r57-h45h', [], 0, DIFFICULTY);
    }

    static mineBlock(lastBlock, data) { // adds (Mines) new block
        let hash, timestamp;
        timestamp = Date.now();
        const lastHash = lastBlock.hash;
        let { difficulty } = lastBlock;
        let nonce = 0;
        do {
            nonce++;
            timestamp = Date.now();
            difficulty = Block.adjustDifficulty(lastBlock, timestamp);
            hash = Block.hash(timestamp, lastHash, data, nonce, difficulty);
        } while(hash.substring(0,difficulty) !== '0'.repeat(difficulty));
        
        return new this(timestamp, lastHash, hash, data, nonce, difficulty);
    }

    static hash(timestamp, lastHash, data, nonce, difficulty) { // generates new hash
        return SHA256(`${timestamp}${lastHash}${data}${nonce}${difficulty}`).toString();
    }

    static blockHash(block) { // checks has validity
        const { timestamp, lastHash, data, nonce, difficulty} = block;

        return Block.hash(timestamp, lastHash, data, nonce, difficulty);
    }

    static adjustDifficulty(lastBlock, currentTime) { // adjusts mining difficulty
        let { difficulty } = lastBlock;
        // if(lastBlock.timestamp + MINE_RATE > currentTime){
        //     difficulty+=1
        // }
        // else{
        //     difficulty-=1;
        // }
        
        difficulty = MINE_RATE >= currentTime - lastBlock.timestamp ? difficulty + 1 : difficulty - 1;
        return difficulty;
    }
}

module.exports = Block;

block.test.js

const Block = require('./Block');

describe('Block', () => {
    let data, lastblock, block;

    beforeEach(() => {
        data = 'bar';
        lastBlock = Block.genesis();
        block = Block.mineBlock(lastBlock, data);
    });
    it('sets the `data` to match the input', () => {
        expect(block.data).toEqual(data);
    });

    it('sets the `lastHash` to match the hash of the last block', () => {
        expect(block.lastHash).toEqual(lastBlock.hash);
    });

    it('generates hash that matches difficulty', () => {
        expect(block.hash.substring(0, block.difficulty)).toEqual('0'.repeat(block.difficulty));
    });

    it('lowers the difficulty for slowly mined blocks', () => {
        expect(Block.adjustDifficulty(block, block.timeStamp+360000)).toEqual(block.difficulty - 1);
    });

    it('raises the difficulty for quickly mined block', () => {
        expect(Block.adjustDifficulty(block, block.timeStamp+1)).toEqual(block.difficulty + 1);
    });
    
});

config.js：

const DIFFICULTY = 3; // difficulty of mining a block
const MINE_RATE = 3000; // mine rate definition 
const GENESIS = Date.now(); // setting date of first block (genesis block)

module.exports = { DIFFICULTY, MINE_RATE, GENESIS };