How to provide mock files to change event of <input type='file'> for unit testing

Question

I\'m having difficulties with a unit test in which I want to verify the processing of a file, which would usually be selected in the view via

Answer 1

UPDATE: Thanks to @PeteBD,

Since angularjs version 1.2.22, the jqLite are now support passing a custom event object to triggerHandler(). See: d262378b

---

If you are using only jqLite,

the triggerHandler() will never work as it will pass a dummy event object to handlers.

The dummy event object look like this (copied from jqLite.js#L962)

{
  preventDefault: noop,
  stopPropagation: noop
}

As you can see, it doesn't even have a target property.

If you are using jQuery,

you could trigger an event with a custom event object like this:

input.triggerHandler({
  type: 'change',
  target: {
    files: fileList
  }
});

and the evt.target.files will be the fileList as you are expecting.

Hope this helps.

Answer 2

Your file change handler should probably be a function directly on your controller. You can bind that function to the change event either from the HTML or a directive. That way you can call your handler function directly without worrying about triggering an event. This egghead.io video covers a couple ways you can do that: https://egghead.io/lessons/angularjs-file-uploads

There are a lot of things you need to worry about when rolling your own file uploader with Angular so I would just use one of the existing libraries out there that takes care of it. e.g. angular-file-upload

Answer 3

Let's rethink AngularJS, DOM must be handled in a directive

We should not deal with DOM element in a controller, i.e. element.on('change', .., especially for testing purpose. In a controller, You talk to data, not to DOM.

Thus, those onchange should be a directive like the following

<input type="file" name='file' ng-change="fileChanged()" /> <br/>

However, unfortunately, ng-change does not work well with type="file". I am not sure that the future version works with this or not. We still can apply the same method though.

<input type="file" 
  onchange="angular.element(this).scope().fileChanged(this.files)" />

and in the controller, we just simply define a method

$scope.fileChanged = function(files) {
  return files.0.length < 500000;
};

Now, everything is just a normal controller test. No more dealing with angular.element, $compile, triggers, etc.! :)

describe(‘MyCtrl’, function() {
  it('does check files', inject(
    function($rootScope, $controller) {
      scope = $rootScope.new();
      ctrl = $controller(‘UploadCtrl’, {‘$scope’: scope});

      var files = { 0: {name:'foo', size: 500001} };
      expect(scope.fileChanged(files)).toBe(true);
    }
  ));
});

http://plnkr.co/edit/1J7ETus0etBLO18FQDhK?p=preview

Answer 4

Here is an example spec for input file/image using angular2+.

it('should call showError on toastService Api on call of onSaveOfImage() method', () => {

    spyOn(component.commonFacade.fileIOApi, 'uploadFile');
    let file = new File([new ArrayBuffer(2e+5)], 'test-file.jpg', { lastModified: null, type: 'image/jpeg' });
    let fileInput={ files: [file] };
    component['onSaveOfImage'](fileInput,"",null,"","");
    expect(component.commonFacade.fileIOApi.uploadFile).toHaveBeenCalledTimes(1);
    expect(component.uploadedFileData).toBeUndefined();
    expect(component.commonFacade.employeeApi.toastService.showError).toHaveBeenCalledTimes(1);
  })