Mongoose / Mocha testing

1

Hello FCC,

I’m working on the url shortener backend challenge and I am stumped with testing one of my functions I’ve written. I’ve written a function createShortUrl() which connects to the db, generates a random string, creates a new url model and calls .save on the object. The function then disconnects from the db and calls the callback. The code looks like this.

function createShortUrl(longUrl, cb){
  mongoose.connect('mongodb://localhost/test', function(err){
    let randShort = sm.randomString();
    let url = new Url({
      long_url: longUrl,
      short_url: randShort
    });

    url.save(function(err){
      if (err) throw err;
      mongoose.disconnect();
      cb();
    }); 
  });
}

I’m writing my tests with mocha and I CANNOT get a test to pass for this function. My test case looks like this

describe('the createShortUrl function', function(){
  it('should create a long:short entry in the db', function(done){
    this.timeout(10000);
    let longUrl = 'http://www.reddit.com';
    url.createShortUrl(longUrl, function(){
      Url.find({}, function(err, docs){ //this Url is a model object
        if (err) throw err;
        expect(docs[0].long_url).to.eql(longUrl);
        expect(typeof docs[0].short_url).to.eql('string')
        expect(docs[0].short_url).to.have.length(5);
        done();
      });
    });
  });
});

when I run my tests with npm test the test does not pass. the error message says Error: Timeout of 10000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.

I originally thought that this may be because when I call the createShortUrl() function I close the connection to the database, so I’ve also tried to open the connection before calling Url.find() like this:

describe('the createShortUrl function', function(){
  it('should create a long:short entry in the db', function(done){
    this.timeout(10000);
    let longUrl = 'http://www.pivotalvoices.com';
    url.createShortUrl(longUrl, function(){
      mongoose.connect('mongodb://localhost/test'); //reconnet to db before calling Url.find
      Url.find({}, function(err, docs){
        if (err) throw err;
        expect(docs[0].long_url).to.eql(longUrl);
        expect(typeof docs[0].short_url).to.eql('string')
        expect(docs[0].short_url).to.have.length(5);
        done();
      });
    });
  });
});

When this code is run I get a different error message:
Uncaught Error: Trying to open unclosed connection.

What’s curious is that in both cases my data is saved correctly to the database — I just can’t get the test to pass and it is driving me crazy. I’ve mulled it over for hours.

Can anyone offer some help with this?

Thanks very much!

2

Remove mongoose.disconnect();

As a rule of thumb you should have

mongoose.connect('mongodb://...');

somewhere at the beginnning of your entry file and you should not do any connects/disconnects later. Mongoose does connection management itself.

1 Like
3

This worked! Thank you so much @jenovs for your help.