Mar3 Mar3 - 6 months ago 23
AngularJS Question

Jasmine, Karma, Angular how to write test on my Angular app?

I have just jumped to another project and, basically, I have been asked to write Unit tests. Since I have already know Protractor for e2e testing, I now switched to Karma and Jasmine to carry out unit testing. I have already downloaded karma, jasmine, karma-jasmine, and karma-chrome-launcher. I installed angular-mocks as well so I should be ready to start. I have read many things on the internet but, now, what I really need is a concrete example of a real app to figure out how to start writing tests. I don't need easy examples but concrete examples and full explenations. Books and useful links are appreciated as well. Thanks in advance for your help/time.

Answer
describe('ServiceBeingTested Name', (): void => {

var mockFirstDependency;
var mockSecondDependency;
var TestedService;

//Mock all dependencies
beforeEach((): void => {

    angular.mock.module('moduleServiceIsIn'); //Register the module which the service is in

    mockFirstDependency = sinon.stub(new MockFirstDependency());//Sinon if useful for mocking
    mockSecondDependency = sinon.stub(new MockSecondDependency());

    angular.mock.module(($provide): void => {
        $provide.value('FirstDependency', mockFirstDependency);
        $provide.value('SecondDependency', mockSecondDependency);
    });
});

beforeEach(inject(
    ['TestedService', (_TestedService_: TestedService): void => {
        TestedService = _TestedService_;
    }]));

//Describe each method in the service
describe('method to test', (): void => {

    it("should...", () => {
        //testing goes in here
        expect(TestedService.someMethod()).toBe("some value");
    });
});

This is a simple example of how to test an angular service. In this case the service is called TestedService.

The first thing you'll see is that three variable declarations. The first two are declared to mock out the two dependencies of this service.(Assume this service has two dependencies). The last variable declaration is going to be assigned the actual service being tested.

Now in the beforeEach:

angular.mock.module

This line registers the module in which the service you are testing is in. This line is very important.

The next two line use Sinon.js to mock the dependencies of the service being tested. I recommend looking into Sinon.js

The way it works is we have a dependency called "FirstDependency" which I created a stub of and called "MockedFirstDependency" and here I created an instance of it.

Now for the next part which (the part that includes $provide)

$provide.value('FirstDependency', mockFirstDependency);

What the above line does is it tells Angular that every time the FirstDependency service is used, instead use mockFirstDependency.

Now in the next beforeEach all I do is inject the actual service which I am testing and assign it to my global variable.

Then let the testing begin

EDIT: Testing Controllers

describe('mainCtrl', (): void => {
    var $controllerConstructor;
    var MainCtrlInstance;
    var mockScope;
    var mockState;
    var mockStates;
    var mockGlobalData;

    beforeEach(() => {
        angular.mock.module('mainCtrlModule');

        mockScope = sinon.stub(new MockScope());
        mockState = sinon.stub(new MockState());
        mockStates = sinon.stub(new MockState());
        mockGlobalData = sinon.stub(new MockGlobalData());

        inject(($controller: ng.IControllerService): void => {
            $controllerConstructor = $controller;
        });

        //Constructs the controller, all dependencies must be injected here
        MainCtrlInstance = $controllerConstructor('mainCtrl',
            {
                '$Scope': mockScope,
                '$State': mockState,
                'States': mockStates,
                'srvGlobalData': mockGlobalData
            }
        );
    });

    describe('Method to Tests', (): void => {

        it("should...", (): void => {
            //Testing Begins
            expect(MainCtrlInstance.method()).toBe("some value");
        });
    });
});

Directives

First off you will need to install Html2JsPreprocessor with this command: npm install karma-ng-html2js-preprocessor --save-dev as stated here.

karma.conf.js

files: [
    //Obviously include all of your Angular files
    //but make sure to include your jQeury before angular.js

    "directory/to/html/directive.html", // include html for directive
    "directive.js" // file directive is contained in
    "directive.spec.js"" // spec file
]

// include the directive html file to be preprocessed
preprocessors: {
    'directory/to/html/directive.html': 'ng-html2js'
},

plugins : [
    'karma-chrome-launcher',
    'karma-jasmine',
    'karma-ng-html2js-preprocessor' //include as a plugin too
],

ngHtml2JsPreprocessor: {
    //this part has a lot of useful features but unfortunately I
    //never got them to work, Google if you need help
},

directive.js

export class myDirectiveController {

    constructor(/*dependencies for controller*/) {
        //initializations
    }
    //other methods for directive class
}

export class myDirective implements ng.IDirective {
    constructor(/*dependencies for directive*/) { }
    static instance(/*dependencies*/): ng.IDirective {
        return new myDirective(/*dependencies for directive*/);
    }

    restrict = 'E';
    templateUrl = 'myDirective.html';
    controller = myDirectiveController;
    controllerAs = 'myDirectiveController';
    scope: {};
}

angular
.module('myDirectiveModule')
.directive('myDirective', myDirective.instance);

myDirective.spec

describe("myDirective", () => {

    //do you variable declarations but I'm leaving them out for simplicity

    beforeEach(() => {

        angular.mock.module(
            'myDirectiveModule', //and other modules in use
            'directory/to/html/directive.html'
            //include directive html as a module
        )

        // now do your mock dependencies as you did with services
        mockDependency = sinon.stub(new MockDependency());

        angular.mock.module(($provide): void => {
            $provide.value('dependency', mockDependency);
        }

        //inject $compile and $rootScope
        inject(($compile, $rootScope) => {

            scope = $rootScope.$new();

            // your directive gets compiled here
            element = angular.element("<my-directive></my-directive>");
            $compile(element)(scope);
            $rootScope.$digest();
            directiveController = element.controller('myDirective'); //this is your directive's name defined in .directive("myDirective", ...)
        });
    }

    describe("simple test", () => {

        it("should click a link", () => {

            var a = element.find("a");

            a.triggerHandler('click');

            //very important to call scope.$digest every you change anything in the view or the model
            scope.$digest();

            expect('whatever').toBe('whatever');
        });

    });
}

Earlier when I stated to included your jQuery file before you Angular, do this because angular.element() will produce a jQuery object on which you can use the jQuery API, but if you do not include jQuery first then you angular.element() returns a jQLite object which contains less methods.

It is also important to call scope.$digest() because that updates the bindings for your directive.

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