How can one properly test the functionality of an AngularJS directive in a way that is commonly accepted and

What is the recommended approach for conducting in-memory integration testing of a directive?

For instance, if there is a directive with a button that changes color when clicked, would the following method be considered standard practice for a DOM integration test?

test-colour-button-directive.js

var ColourButtonDirective = require('../colour-button-directive');

describe('coloured button', function() {

    var $compile, $rootScope;

    beforeEach(inject(function($templateCache, $rootScope, $injector) {
      // Is it appropriate to configure the module in the beforeEach block?   
      angular.module('test', [])
            .directive('colourButton', ColourButtonDirective);
        $templateCache.put('./colour-button.html');            
        $compile = $injector.get('$compile'); // Can $compile be injected directly?
    }));

    it('should change to red when clicked', function() {
        //prepare
        var dom, button;
        dom = $compile(angular.element('<colour-button></colour-button>'))($rootScope); // Do I need to provide a scope to the link function invocation?
        button = angular.element(dom.querySelector('button')); // Is there a more efficient way to access the button within the rendered DOM?

        //execute
        button.click();

        //validate
        expect(button.css('background-color')).toBe('red');
    });

});

colour-button.html

<button ng-click='onClick'>My button</button>

colour-button-directive.js

return function ColourButtonDirective() {
    return {
        scope: {
            onClick: function($event) {
                $event.currentTarget.css('background-color', 'red');
            }
        },
        restrict: 'E',
        template: require('./colour-button.html'),
        replace: true,
    };
};

Answer №1

To start, let's address the questions you raised in the comments:

// Should configuration of the module be located in the beforeEach?   
angular.module('test', [])
  .directive('coloredButton', ColoredButtonDirective);

An alternative approach would be to use

beforeEach(module('test'));

as demonstrated at https://code.angularjs.org/1.4.7/docs/guide/unit-testing. Therefore, the line instantiating your app from your actual code

var app = angular.module('test', []);

should be executed in the test environment.

$compile = $injector.get('$compile'); // Can I have $compile injected instead?

Indeed, you can achieve this by

beforeEach(inject(function(_$rootScope_, _$compile_) {
  $rootScope = _$rootScope_;
  $compile = _$compile_;
}));

Introducing a scope into $compile

dom = $compile(angular.element('<colored-button></colored-button>'))($rootScope); // Must I inject a scope to the invocation of the link function?

Yes, it is necessary. You have the option to compile an element once and then link against various scopes to generate different DOM elements from the same compiled version. (This mimics what ng-repeat does behind the scenes).

button = angular.element(dom.querySelector('button')); // Is there a better way of getting the button inside the rendered DOM?

Possibly, but as currently written, the line may not function due to two reasons:

  • dom is a jQlite object that lacks a querySelector method
  • dom is a jQlite object representing the root of the directive, which happens to be a button, thus finding the button directly won't yield results.

However, if the DOM structure varies, you could consider:

button = dom.find('button');

In addition to your queries:

//act
button.click();

This would not work since jQlite doesn't support a 'click' function. An alternative action would be:

dom.triggerHandler('click');

Furthermore,

scope: {
  onClick: function($event) {
    $event.currentTarget.css('background-color', 'red');
  }
}

would not be effective since this isn't the correct manner to utilize the scope object within the directive definition. For functionality, it has to be placed in the link function and rely on $event.target instead

link: function(scope, element, attrs) {
  scope.onClick = function($event) {
    angular.element($event.target).css('background-color', 'red');
  }
}

Additionally, to execute it and pass the $event object correctly, the template ought to be

<button ng-click='onClick'>My button</button>

which should be changed to

<button ng-click='onClick($event)'>My button</button>

A compilation of all these changes yields a directive like

app.directive('coloredButton', function ColoredButtonDirective() {
  return {
    scope: {
    },
    restrict: 'E',
    template: '<button ng-click="onClick($event)">My button</button>',
    replace: true,
    link: function(scope, element, attrs) {
      scope.onClick = function($event) {
        angular.element($event.target).css('background-color', 'red');
      }
    }
  };
});

and its respective test:

describe('colored button', function() {
  var $compile, $rootScope;

  beforeEach(module('test'));

  beforeEach(inject(function(_$rootScope_, _$compile_) {
    $rootScope = _$rootScope_;
    $compile = _$compile_;
  }));

  it('should turn red when clicked', function() {
    var dom, button;
    dom = $compile(angular.element('<colored-button></colored-button>'))($rootScope);
    dom.triggerHandler('click');
    expect(dom.css('background-color')).toBe('red');
  });

For more details you can check the original links provided.

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

Error in Postman: Express and Mongoose throwing 'name' property as undefined

While trying to create and insert 'user' JSON documents according to the model below, upon sending a POST request to localhost:3000/api/student, I encountered an error using Postman: TypeError: Cannot read property 'name' of undefined ...

Stop options from being hidden in a select dropdown using HTML

Can I keep the options visible when a user selects an item in the 'select' dropdown? I want to add more options to the 'select' when the user clicks on the 'op2' item, without closing the list of options. <select> <o ...

Error Encountered in NextJS - Hydration Unsuccessful

Currently, I am utilizing NextLink in my project to generate links. However, it appears that using NextLink is causing the following error: Hydration failed because the initial UI does not match what was rendered on the server. Upon inspecting the console ...

Utilize Vue-cli 3.x to load static resources

In my vue-cli 3 project, I have organized the static assets in the public directory. When compiled and built on localhost, all assets load successfully, except for some images not appearing in the browser. Despite guyana-live-logo.png, slide-1.jpg, and 97 ...

When working in my AngularJS controller, I encountered an issue where I was attempting to append a dynamic value from the view to the URL,

In the view below, I am utilizing the ID appended to the URL in the controller to retrieve the corresponding book: <div ng-controller="viewBookController"> <form ng-submit="getBook()"> Your ID:<input type="text" ng-model="id"/><br ...

Error occurred while fetching image from Medium story API in Next.js

While working on my Next.js app, I encountered an issue with the Medium story API. Every time I try to fetch and display an image using the API, I receive an error message stating "upstream image response failed." The specific error code is: upstream image ...

axios error: Trying to access 'slice' property of null object

Encountered an error while implementing server-side rendering with Redux in React Error Details: TypeError: Cannot read property 'slice' of null at dispatchHttpRequest (E:\Projects\real-estate\node_modules\axios\li ...

Is it possible to recreate the initial JavaScript source file using a minified version alongside its associated source-map file?

Currently, I am tackling a project that involves statically analyzing JavaScript code. The challenge lies in the fact that for certain libraries, I am limited to only having a minified version of the file along with its corresponding source-map. Are ther ...

Can a 1D array be utilized to create a 2D grid in React?

I needed to display a one-dimensional array in a 2D grid format with 3 rows and 3 columns. The array itself contains numbers from 1 to 9. const array = Array.from({ length: 9 }, (_, i) => i + 1); In my React component, I have it rendering as a series o ...

How can I retrieve the children of a component in React?

Currently, I am working on implementing Class Components for a project involving a main picture and a smaller pictures gallery stored in an array. The overall structure consists of an all pictures container that houses both the main picture and smaller pic ...

Encountering issues when setting fitbounds beyond the scope of a jquery.each()

I am currently working on a Google Map project using JavaScript(v3). My goal is to display markers from XML data by utilizing jQuery. Below are the object and function that I have created to streamline this process: var VX = { map:null, bounds ...

What is the best way to store and retrieve data from the current webpage using HTML, CSS, and JavaScript?

Is there a way to persistently save the button created by the user even when the browser is refreshed? Here is an example code snippet: function create(){ const a = document.createElement("button") document.body.appendChild(a) const b = documen ...

Rearrange the layout by dragging and dropping images to switch their places

I've been working on implementing a photo uploader that requires the order of photos to be maintained. In order to achieve this, I have attempted to incorporate a drag and drop feature to swap their positions. However, I am encountering an issue where ...

developing an associative object/map in JavaScript

I have a form featuring various groups of checkboxes and I am attempting to gather all the selected values into an array, then pass that data into an Ajax request. $('#accessoriesOptions input').each(function(index, value){ if($(this).prop(& ...

Determining the largest range possible in a sorted array of integers

I need help with a JavaScript implementation for the following challenge. Imagine we have a sorted array: [1,2,5,9,10,12,20,21,22,23,24,26,27] I want to find the length of the longest consecutive range that increments by 1 without duplicates. In the ...

Modify the color of every element by applying a CSS class

I attempted to change the color of all elements in a certain class, but encountered an error: Unable to convert undefined or null to object This is the code I used: <div class="kolorek" onclick="changeColor('34495e');" style="background-c ...

Putting AngularJS Directives to the Test with Jest

There seems to be a crucial element missing in my overly simplified angular directive unit test. The directive code looks like this: import * as angular from 'angular' import 'angular-mocks' const app = angular.module('my-app&apo ...

Enhancing game menus for various mobile screen sizes

I've noticed a consistent pattern in the games I download from the Google Play Store - they all have a background image at the menu with clickable buttons. When testing these games on different devices, I found that the backgrounds didn't stretch ...

How to work with a JSON object in Internet Explorer 6

Looking for some quick answers that should be easy for someone with expertise to provide. I have a basic asp.net site that relies on JSON for various tasks (and JSON.stringify). Everything works fine in Firefox and the like, but in IE6 I'm getting a ...

AJAX - Self-Executing Anonymous Function

I have a question that may seem trivial, but I want to make sure I'm heading in the right direction. I've created two different versions of an XMLHttpRequest wrapper, and both are functioning correctly. const httpRequest = function () { let ...