错误:在实例化契约对象时，必须提供契约的json接口。

Question

这就是当我尝试测试我的合同时发生的错误。

有人能告诉我问题出在哪里吗？

这是测试的代码：

const assert = require('assert');
const fs = require('fs');
const ganache = require('ganache-cli');
const Web3 = require('web3');
const web3 = new Web3(ganache.provider());

const compiledFactory = fs.readFileSync('./ethereum/build/LotteriaFactory.json', 'utf8');
const compiledLotteria = fs.readFileSync('./ethereum/build/Lotteria.json', 'utf8');

let accounts;
let factory;
let lotteriaAddress;
let lotteria;

beforeEach(async () => {
  accounts = await web3.eth.getAccounts();

  factory = await new web3.eth.Contract(JSON.parse(compiledFactory).interface)
  .deploy({ data: (compiledFactory).bytecode })
  .send({ from: accounts[0], gas: '1000000' });

  await factory.methods.createNew('5').send({
    from: accounts[0], //manager
    gas: '1000000'
  });

  const addresses = await factory.methods.active().call();
  lotteriaAddress = addresses[0]; //[LotteriaFactory]

   lotteria = new web3.eth.Contract(
     JSON.parse(compiledFactory).interface,
     lotteriaAddress
   );
});

describe('Lotteria', () => {
  it('deploy a factory and a lottery', () => {
    assert.ok(factory.options.address);
    assert.ok(lotteria.options.address);
  });
});

Answer 1

您可以尝试这样的方法来实例化一个契约：

• 将合同的abi复制到json文件中
• 读取文件：const contractJson = fs.readFileSync('path_to_abi_file.json');
• 解析文件：const abi = JSON.parse(contractJson);
• 实例化契约：contractInstance = new web3.eth.Contract(abi);