qipai/backend/tests/wechat-pay.test.mjs

import assert from 'node:assert/strict';
import {
  createCipheriv, createSign, generateKeyPairSync, randomBytes
} from 'node:crypto';
import {
  WechatPayClient, WechatPayError
} from '../dist/payments/wechat-pay-client.js';

const merchantKeys = generateKeyPairSync('rsa', {
  modulusLength: 2048,
  publicKeyEncoding: { type: 'spki', format: 'pem' },
  privateKeyEncoding: { type: 'pkcs8', format: 'pem' }
});
const platformKeys = generateKeyPairSync('rsa', {
  modulusLength: 2048,
  publicKeyEncoding: { type: 'spki', format: 'pem' },
  privateKeyEncoding: { type: 'pkcs8', format: 'pem' }
});
const credential = {
  appId: 'wx-test-app',
  merchantId: '1900000109',
  serialNo: 'MERCHANT-SERIAL',
  privateKeyPem: merchantKeys.privateKey,
  apiV3Key: '0123456789abcdef0123456789abcdef',
  platformCertificates: { 'PLATFORM-SERIAL': platformKeys.publicKey }
};
const requests = [];
const responses = [
  { prepay_id: 'wx-prepay-test' },
  { trade_state: 'SUCCESS', transaction_id: 'wx-transaction-test' },
  { refund_id: 'wx-refund-test', status: 'PROCESSING' },
  { download_url: 'https://api.mch.weixin.qq.com/v3/billdownload/file?token=sanitized' },
  {
    out_bill_no: 'CLP501',
    transfer_bill_no: 'wx-transfer-501',
    state: 'WAIT_USER_CONFIRM',
    package_info: 'package-info'
  },
  {
    mch_id: '1900000109',
    out_bill_no: 'CLP501',
    transfer_bill_no: 'wx-transfer-501',
    state: 'SUCCESS',
    transfer_amount: 800
  }
];
const transport = {
  async request(input) {
    requests.push(input);
    return {
      status: 200,
      headers: {},
      body: JSON.stringify(responses.shift())
    };
  }
};
const client = new WechatPayClient(transport);
const prepay = await client.createJsapiPrepay(credential, {
  description: 'M05-B sanitized order',
  outTradeNo: 'PAY-M05B-001',
  notifyUrl: 'https://api.txyundm.cn/app-api/pay/wechat/notify',
  amountCents: 3600,
  payerOpenId: 'openid-sanitized'
});
assert.equal(prepay.prepayId, 'wx-prepay-test');
assert.equal(prepay.paymentParams.package, 'prepay_id=wx-prepay-test');
assert.equal(prepay.paymentParams.signType, 'RSA');
assert.match(prepay.paymentParams.paySign, /^[A-Za-z0-9+/]+=*$/);
assert.match(requests[0].headers.Authorization, /mchid="1900000109"/);
assert.equal(requests[0].body.includes(merchantKeys.privateKey), false);

assert.equal(
  (await client.queryTransaction(credential, 'PAY-M05B-001')).trade_state,
  'SUCCESS'
);
assert.equal((await client.createRefund(credential, {
  outTradeNo: 'PAY-M05B-001',
  outRefundNo: 'REF-M05B-001',
  reason: 'sanitized refund',
  notifyUrl: 'https://api.txyundm.cn/app-api/pay/wechat/refund-notify',
  refundCents: 1200,
  totalCents: 3600
})).status, 'PROCESSING');
assert.match(requests[2].body, /"refund":1200/);
assert.match((await client.downloadTradeBill(
  credential, '2026-06-21', 'ALL'
)).download_url, /^https:/);

const transfer = await client.createMerchantTransfer(credential, {
  outBillNo: 'CLP501',
  openid: 'openid-sanitized',
  amountCents: 800,
  remark: '保洁结算501',
  sceneId: '1000',
  reportInfos: [{ infoType: '岗位类型', infoContent: '保洁员' }]
});
assert.equal(transfer.state, 'WAIT_USER_CONFIRM');
assert.equal(transfer.packageInfo, 'package-info');
assert.match(requests[4].url, /\/v3\/fund-app\/mch-transfer\/transfer-bills$/);
assert.match(requests[4].body, /"out_bill_no":"CLP501"/);
assert.match(requests[4].body, /"transfer_amount":800/);
assert.equal(requests[4].headers.Authorization.includes(merchantKeys.privateKey), false);

const queriedTransfer = await client.queryMerchantTransferByOutBillNo(credential, 'CLP501');
assert.equal(queriedTransfer.state, 'SUCCESS');
assert.equal(queriedTransfer.amountCents, 800);
assert.match(requests[5].url, /\/v3\/fund-app\/mch-transfer\/transfer-bills\/out-bill-no\/CLP501$/);
assert.equal(requests[5].headers.Authorization.includes(merchantKeys.privateKey), false);

const notification = encryptedNotification({
  out_trade_no: 'PAY-M05B-001',
  transaction_id: 'wx-transaction-test',
  trade_state: 'SUCCESS',
  amount: { total: 3600, currency: 'CNY' },
  payer: { openid: 'must-not-be-persisted' }
}, credential.apiV3Key);
const timestamp = '1782057600';
const nonce = 'notification-nonce';
const signature = sign(
  platformKeys.privateKey,
  `${timestamp}\n${nonce}\n${notification}\n`
);
const decrypted = client.verifyAndDecrypt(credential, {
  timestamp,
  nonce,
  serial: 'PLATFORM-SERIAL',
  signature
}, notification);
assert.equal(decrypted.transaction_id, 'wx-transaction-test');
assert.equal(decrypted.amount.total, 3600);
assert.throws(
  () => client.verifyAndDecrypt(credential, {
    timestamp,
    nonce,
    serial: 'PLATFORM-SERIAL',
    signature
  }, `${notification} `),
  (error) => error instanceof WechatPayError
    && error.code === 'WECHAT_SIGNATURE_INVALID'
);

console.log('PASS: M05-B Wechat Pay signing, API requests, notification verification and AES-GCM decryption.');

function encryptedNotification(resource, key) {
  const nonce = randomBytes(12).toString('base64url').slice(0, 12);
  const associatedData = 'transaction';
  const cipher = createCipheriv('aes-256-gcm', Buffer.from(key), Buffer.from(nonce));
  cipher.setAAD(Buffer.from(associatedData));
  const ciphertext = Buffer.concat([
    cipher.update(JSON.stringify(resource), 'utf8'),
    cipher.final(),
    cipher.getAuthTag()
  ]).toString('base64');
  return JSON.stringify({
    id: 'notification-m05b-001',
    event_type: 'TRANSACTION.SUCCESS',
    resource: {
      algorithm: 'AEAD_AES_256_GCM',
      ciphertext,
      nonce,
      associated_data: associatedData
    }
  });
}

function sign(privateKey, message) {
  const signer = createSign('RSA-SHA256');
  signer.update(message);
  signer.end();
  return signer.sign(privateKey, 'base64');
}