Mocha、Chai 和 Sinon 未处理的承诺拒绝警告

Question

我正在使用Node并且有以下ES6类：

const moment = require('moment');

const sqlFileReader = require('../database/SqlFileReader');
const Lnfe = require('../errors/LoanNotFoundError');

const epoch = '1970-01-01';

/**
 * Take the input params and return the clientId (either found via loanId or untouched) and dateString we need
*/
class ParameterParser {

static async prepareInputParameters(con, req) {

    let clientId = req.query.client_id; // Will be overriden if we need and are able to obtain the client id via loan id.
    let dateString;

    // If no client_id is given but loan_id is, get the client_id via loan_id:
    if (typeof req.query.client_id === 'undefined' && typeof req.query.loan_id !== 'undefined') {
        const { retData } = await sqlFileReader.read('./src/database/sql/getClientIdFromLoanId.sql', [`${req.query.loan_id}`], con, req.logger);
        if (retData.rowsCount > 0) {
            clientId = retData.rows[0].client_id;
        }
        else {
            throw new Lnfe(400, req);
        }
    }

    if (typeof req.query.complaint_init_date === 'undefined') {
        dateString = epoch;
    }
    else {
        // Need to subtract 6 years from the complaint_init_date:
        dateString = moment(moment(req.query.complaint_init_date, 'YYYY-MM-DD').toDate()).subtract(6, 'years').format('YYYY-MM-DD');
    }

    return { clientId, dateString };
}

}

module.exports = ParameterParser;

我正在使用Mocha 、 Chai 、 Chai-as-Promised和Sinon测试它：

'use strict';

const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');
const sinon = require('sinon');

const parameterParser = require('../../src/core/ParameterParser.js');
const sqlFileReader = require('../../src/database/SqlFileReader.js');
const Lnfe = require('../../src/errors/LoanNotFoundError');

chai.use(chaiAsPromised);
const { expect } = chai;

const retData = {
rowsCount: 1,
rows: [{ client_id: 872 }],
};

const reqDateAndLoan = {
query: {
    complaint_init_date: '2022-03-15',
    loan_id: '1773266',
},
};

const reqDateAndClient = {
query: {
    complaint_init_date: '2022-03-15',
    client_id: '872',
},
};

const reqDateAndLoanIdThatDoesNotExist = {
query: {
    complaint_init_date: '2022-03-15',
    loan_id: '1773266999999999999',
},
};

describe('prepareInputParameters', () => {

sinon.stub(sqlFileReader, 'read').returns({ retData });

it('results in correct client id and date string', async () => {
    const ret = { clientId: 872, dateString: '2016-03-15' };
    expect(await parameterParser.prepareInputParameters(null, reqDateAndLoan)).to.deep.equal(ret);
});

it('results in a client id equal to the that input if the request query contains a client id', async () => {
    const ret = { clientId: '872', dateString: '2016-03-15' };
    expect(await parameterParser.prepareInputParameters(null, reqDateAndClient)).to.deep.equal(ret);
});

it('throws a \'Loan Not Found\' error', async () => {
    expect(parameterParser.prepareInputParameters(null, reqDateAndLoanIdThatDoesNotExist)).eventually.throw(Lnfe, 400, 'Loan Not Found');
});

it('DOES NOT throw a \'Loan Not Found\' error', async () => {
    expect(async () => {
        await parameterParser.prepareInputParameters(null, reqDateAndLoanIdThatDoesNotExist);
    }).to.not.throw(Lnfe, 400, 'Loan Not Found');
});


});

测试通过，但输出有几个节点警告：

prepareInputParameters
✓ results in correct client id and date string
✓ results in a client id equal to the that input if the request query contains a client id
✓ throws a 'Loan Not Found' error
(node:23875) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): AssertionError: Loan Not Found: expected { Object (clientId, dateString) } to be a function
(node:23875) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
✓ DOES NOT throw a 'Loan Not Found' error


4 passing (19ms)

任何想法如何摆脱这些警告或我做错了什么？

Answer 1

一些想法可以帮助你理解我用 ES6 类编译的 promise 的不同阶段（例子，即）：

// 异步承诺拒绝.js

class asyncpromise{ 
    constructor(s){
        this.s=s
    }
PTest(){    
    var somevar = false;
    somevar=this.s;
    return new Promise(function (resolve, reject) {
        if (somevar === true)
            resolve();
 //       else
   //         reject();
    });
}
}
module.exports=asyncpromise

注释掉 else 部分后，如果 true 传递给类，promise 将解决，或者测试将超时，因为当值为 false 时，promise 不知道该怎么做。

// 测试.js

const asyncpromise=require('./asyncpromiserejection.js')
describe("asyncTests", () => {
it("handles Promise rejection",async ()=>{
    var t=new asyncpromise(false)
    await t.PTest().then(function () {
     console.log("Promise Resolved");
})
})        
});

图 1.0

取消对 else 部分的注释，您将得到相同的错误，但警告承诺拒绝已被弃用 - 图 1.1 - 因为现在，尽管在代码中处理了由于 falsey 值导致的承诺拒绝，但测试即调用方法，没处理过。

class asyncpromise{ 
    constructor(s){
        this.s=s
    }
PTest(){    
    var somevar = false;
    somevar=this.s;
    return new Promise(function (resolve, reject) {
        if (somevar === true)
            resolve();
        else
            reject();
    });
}
}
module.exports=asyncpromise

图 1.1

现在，像这样处理测试中的承诺拒绝：

const asyncpromise=require('./asyncpromiserejection.js')
describe("asyncTests", () => {
it("handles Promise rejection",async ()=>{
    var t=new asyncpromise(false)
    await t.PTest().then(function () {
     console.log("Promise Resolved");
}).catch(()=>{console.log("Promise rejcted")})
})        
});

并且，您可以在 promise 的拒绝部分传递一些自定义消息以在测试中断言，如下所示：

const assert=require('chai').assert
const asyncpromise=require('./asyncpromiserejection.js')
describe("asyncTests", () => {
it("handles Promise rejection",async ()=>{
    var t=new asyncpromise(false)
    await t.PTest().then(function () {
     console.log("Promise Resolved");
}).catch((error)=>{
    console.log("Promise rejected")
    assert.equal(error.message,"Promise rejected")
})
})        
});

// 异步承诺拒绝.js

class asyncpromise{ 
    constructor(s){
        this.s=s
    }
PTest(){    
    var somevar = false;
    somevar=this.s;
    return new Promise(function (resolve, reject) {
        if (somevar === true)
            resolve();
        else
           throw new Error("Promise rejcted")
            //reject();
    });
}
}
module.exports=asyncpromise

Answer 2

我用来捕捉未处理的拒绝使用

process.on('unhandledRejection', (err, p) => {
  console.error('unhandledRejection', err.stack, p)
})

所以我有跟踪，我可以找到并修复

对于DeprecationWarning应该可以工作 - 我不确定，但相应的文档https://nodejs.org/api/process.html#process_event_warning

process.on('warning', (warning) => {
  console.warn(warning.name);
  console.warn(warning.message);
  console.warn(warning.stack);
});