Testing XMLHttpRequest with Jasmine: A Complete Guide

Question

Testing XMLHttpRequest with Jasmine: A Complete Guide

Is there a way to test the onreadystatechange function on XMLHttpRequest or pure JavaScript AJAX without using jQuery? I need to do this because I'm working on a Firefox extension. It seems like I may have to use spies, but I'm having trouble because my AJAX request isn't returning anything.


    submit : function() {
        var url = window.arguments[0];
        var request = new XMLHttpRequest();
        request.open("POST", 'http://'+this.host+'/doSomething', true);
        request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
        request.send("param="+param+"&emotions="+this.getParams());
        request.onreadystatechange = function() {
            if(this.readyState == 4) {
                // alert(this.responseText);
            }
        };

    }

javascript ajax jasmine

Answer 1

Answer №1

How about this one?

beforeEach(function() {
  // spyOn(XMLHttpRequest.prototype, 'open').andCallThrough(); // Jasmine 1.x
  spyOn(XMLHttpRequest.prototype, 'open').and.callThrough(); // Jasmine 2.x
  spyOn(XMLHttpRequest.prototype, 'send');
});

...

it("should verify the appropriate YQL! API call", function() {
  podcast.load_feed('http://www.example.com/feeds/sample-feed/');

  expect(XMLHttpRequest.prototype.open).toHaveBeenCalled();
});

A purely Jasmine-based approach without relying on external libraries.

Answer 2

How about this one?

beforeEach(function() {
  // spyOn(XMLHttpRequest.prototype, 'open').andCallThrough(); // Jasmine 1.x
  spyOn(XMLHttpRequest.prototype, 'open').and.callThrough(); // Jasmine 2.x
  spyOn(XMLHttpRequest.prototype, 'send');
});

...

it("should verify the appropriate YQL! API call", function() {
  podcast.load_feed('http://www.example.com/feeds/sample-feed/');

  expect(XMLHttpRequest.prototype.open).toHaveBeenCalled();
});

A purely Jasmine-based approach without relying on external libraries.

Answer 3

Answer №2

Jasmine's unique feature includes a custom Ajax mock library known as ajax.js, which can be found at this link.

Answer 4

Jasmine's unique feature includes a custom Ajax mock library known as ajax.js, which can be found at this link.

Answer 5

Answer №3

Like stated in the remarks using SinonJS, you have the ability to simulate the XHR object or generate a simulated server.

Answer 6

Like stated in the remarks using SinonJS, you have the ability to simulate the XHR object or generate a simulated server.

Answer 7

Answer №4

One way to test this is as follows:

it("verifies XHR request is made", function() {

   // setting up

    var xhrObj = {
        open: jasmine.createSpy('open')
    };

    XMLHttpRequest = jasmine.createSpy('XMLHttpRequest');
    XMLHttpRequest.and.callFake(function () {
        return xhrObj;
    });

    // executing the action

    submit();

    // validating the result

    expect(xhrObj.open).toHaveBeenCalled(); 
});

Answer 8

One way to test this is as follows:

it("verifies XHR request is made", function() {

   // setting up

    var xhrObj = {
        open: jasmine.createSpy('open')
    };

    XMLHttpRequest = jasmine.createSpy('XMLHttpRequest');
    XMLHttpRequest.and.callFake(function () {
        return xhrObj;
    });

    // executing the action

    submit();

    // validating the result

    expect(xhrObj.open).toHaveBeenCalled(); 
});

Answer 9

Answer №5

Information sourced from jasmine-ajax. For mocking in a specific spec, utilize the withMock function:

  it("can be used in a single spec", function() {
    var doneFn = jasmine.createSpy('success');
    jasmine.Ajax.withMock(function() {
      var xhr = new XMLHttpRequest();
      xhr.onreadystatechange = function(args) {
        if (this.readyState == this.DONE) {
          doneFn(this.responseText);
        }
      };

      xhr.open("GET", "/some/cool/url");
      xhr.send();

      expect(doneFn).not.toHaveBeenCalled();

      jasmine.Ajax.requests.mostRecent().respondWith({
        "status": 200,
        "responseText": 'in spec response'
      });

      expect(doneFn).toHaveBeenCalledWith('in spec response');
    });
  });

The response is triggered by using respondWith. Simply download the file, and include it as a src in your SpecRunner.html. An example of its application can be found at https://github.com/serv-inc/JSGuardian (refer to the test folder).

Answer 10

Information sourced from jasmine-ajax. For mocking in a specific spec, utilize the withMock function:

  it("can be used in a single spec", function() {
    var doneFn = jasmine.createSpy('success');
    jasmine.Ajax.withMock(function() {
      var xhr = new XMLHttpRequest();
      xhr.onreadystatechange = function(args) {
        if (this.readyState == this.DONE) {
          doneFn(this.responseText);
        }
      };

      xhr.open("GET", "/some/cool/url");
      xhr.send();

      expect(doneFn).not.toHaveBeenCalled();

      jasmine.Ajax.requests.mostRecent().respondWith({
        "status": 200,
        "responseText": 'in spec response'
      });

      expect(doneFn).toHaveBeenCalledWith('in spec response');
    });
  });

The response is triggered by using respondWith. Simply download the file, and include it as a src in your SpecRunner.html. An example of its application can be found at https://github.com/serv-inc/JSGuardian (refer to the test folder).

Answer 11

Answer №6

By examining the code provided, it appears that injecting console.log() with the status code and status text can help in identifying any http errors.

It is speculated that the status will return 404 in this scenario.

submit : function() {
    var url = window.arguments[0];
    var request = new XMLHttpRequest();
    request.open("POST", 'http://'+this.host+'/doSomething', true);
    request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    request.send("param="+param+"&emotions="+this.getParams());
    request.onreadystatechange = function() {
        console.log(this.status+ " - "+ this.statusText);
    };

}

Alternatively, you can inspect the request header / response within the firebug console. It's worth noting that if firebug or chrome dev tools are not being used, caution should be taken when changing the console.log() call to append the string to a document object and avoid using an alert() call.

How do I verify jQuery AJAX events with Jasmine?. A similar answer that demonstrates how to implement Jasmine for testing.

Answer 12

By examining the code provided, it appears that injecting console.log() with the status code and status text can help in identifying any http errors.

It is speculated that the status will return 404 in this scenario.

submit : function() {
    var url = window.arguments[0];
    var request = new XMLHttpRequest();
    request.open("POST", 'http://'+this.host+'/doSomething', true);
    request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    request.send("param="+param+"&emotions="+this.getParams());
    request.onreadystatechange = function() {
        console.log(this.status+ " - "+ this.statusText);
    };

}

Alternatively, you can inspect the request header / response within the firebug console. It's worth noting that if firebug or chrome dev tools are not being used, caution should be taken when changing the console.log() call to append the string to a document object and avoid using an alert() call.

How do I verify jQuery AJAX events with Jasmine?. A similar answer that demonstrates how to implement Jasmine for testing.

Testing XMLHttpRequest with Jasmine: A Complete Guide

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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