CODEWITHSUNDEEP
javascriptpromisemocha.jssinonpg-promise
Jayaram
Jayaram

Reputation: 6606

How to properly stub a promise object which is part of another promise

I have a promise function which performs an authentication based on the clients cookie

const getInitialState = (id_token) => {
  let initialState;
  return new Promise((resolve,reject) => {
    if(id_token == null){
      initialState = {userDetails:{username: 'Anonymous',isAuthenticated: false}}
      resolve(initialState)
    }else{
        var decoded = jwt.verify(JSON.parse(id_token),'rush2112')
        db.one('SELECT  * FROM account WHERE account_id = $1',decoded.account_id)
          .then(function(result){
            console.log('result is : ',result)
            initialState = {userDetails:{username:result.username,isAuthenticated:true}}
            resolve(initialState)
          })
          .catch(function(err){
            console.log('There was something wrong with the token',e)
            reject('There was an error parsing the token')
          })
    }
  })
}

getInitialState is a promise object which calls a database function(another promise object) if the cookie is valid.

I want to stub the db call here to resolve to a username. But its not working no matter what i try

i tried two libraries sinonStubPromise and sinon-as-promised. But both seem to result in a timeout error which tells me that the db function isnt getting resolved

I believe i'm not stubbing the db function properly

these are the various ways i've tried

stub2 = sinon.stub(db,'one')

stub2.returnsPromise().resolves({username:'Kannaj'})

or

sinon.stub(db,'one').returns({username:'Kannaj'})

or

sinon.stub(db,'one')
         .withArgs('SELECT  * FROM account WHERE account_id = $1',1)
         .returns({username:'Kannnaj'})

or

let db = sinon.stub(db).withArgs('SELECT  * FROM account WHERE account_id = $1',1).returns({username:'Kannnaj'})

all lead to a timeout error from mocha

Error: timeout of 2000ms exceeded. Ensure the done() callback is being called in this test.

this is my entire test function

  it('should return a valid user if id_token is valid',function(){
    id_token = '{"account_id":1}'
    console.log('stub1: ',stub1(), typeof(stub1))
    console.log('stub2 : ',stub2,typeof(stub2))

    // my attempts here
    return expect(getInitialState(id_token)).to.eventually.be.true
  })

For some reason , i believe mocha/sinon is loosing the pg-promise context as soon as it calls db.any . not sure why.

Upvotes: 1

Views: 4071

Answers (1)

boneskull
boneskull

Reputation: 1199

I can't speak to sinon-as-promised or sinonStubPromise, but you don't need them to accomplish something like this.

const sinon = require('sinon');
const chai = require('chai');
chai.use(require('chai-as-promised'));
const expect = chai.expect;

// real object
const db = {
  one: function () {
    // dummy function
  }
};

// real function under test
function foo () {
  return db.one('SELECT * FROM account WHERE account_id = $1');
}

describe('foo', function () {
  beforeEach(function () {
    sinon.stub(db, 'one')
      .withArgs('SELECT * FROM account WHERE account_id = $1')
      .returns(Promise.resolve({username: 'Kannaj'}));
  });

  it('should not timeout', function () {
    return expect(foo())
      .to
      .eventually
      .eql({username: 'Kannaj'});
  });

  afterEach(function () {
    db.one.restore();
  });
});

Upvotes: 1

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