CODEWITHSUNDEEP
ajaxunit-testingjasminesuperagent
Kevin Whitaker
Kevin Whitaker

Reputation: 13435

Javascript: How to spy on superagent with Jasmine?

I'm using the superagent ajax library for an app, and I'm trying to write some unit tests for it. I've got a class which looks like this:

someClass = {
  getData: function(){
    _this = this;
    superagent.get('/some_url').end(function(res){
      if(res.body){
        _this.data = res.body
      }
     });
   });
 }

How do I write a Jasmine test to spy on the _this.data = res.body call? Setting up a spy with and.callThrough() on getData isn't working. I don't want to actually call the URL in question; I'm just trying to test that if it gets data, it does something with it.

Thanks

Upvotes: 8

Views: 1049

Answers (4)

FlavorScape
FlavorScape

Reputation: 14319

Say it's a patch, first make a mock patch return value:

this.mockPatchObject = {
      set: () => {
        return {
          end: (cb: any) => {
            cb(null, {body: 'etc'});
          },
        };
      },
    };

then return it as the value of patch: 

this.superagentSpy = spyOn(request,'patch').and.returnValue(this.mockPatchObject);

then spy on the set function of the "mock" patch object:

this.superagentSetSpy = spyOn(this.mockPatchObject, 'set');

Upvotes: 0

Toni Leigh
Toni Leigh

Reputation: 4969

There's another good solution here, which is to abstract out the anonymous function:

someClass = {
  getData: function(){
    _this = this;
    superagent.get('/some_url').end(this.handleAjax);
  },

  handleAjax: function(res){
    if(res.body){
      _this.data = res.body
    }
  }
}

Now you can test the handleAjax function discretely and with simple tests; and also stub superagent as you only need to check a method .end() is called on it with a particular value.

Anonymous functions are problematic for other reasons than just testing so this is a good refactor

Upvotes: 0

udayanga
udayanga

Reputation: 421

Bror's answer works perfectly. To add something to his answer, when we need to add another superagent function (like set) to the spyOn method, you can use as follows.

spyOn(superagent, 'get').and.callFake(function(url) {
  return {
      set: function() {
        return {
          end: function(cb) {
            //null for no error, and object to mirror how a response would look.
            cb(null, {body: data});
          }
        }
     }
});

Here, the set function is used to set headers to the request.

Upvotes: 0

Bror
Bror

Reputation: 1435

spyOn(superagent, 'get').and.callFake(function(url) {
  return {
    end: function(cb) {
      //null for no error, and object to mirror how a response would look.
      cb(null, {body: data});
    }
  }
});

Upvotes: 3

Related Questions