Exploring AngularJS and Jasmine: Testing a controller function that interacts with a service via $http

Question

Exploring AngularJS and Jasmine: Testing a controller function that interacts with a service via $http

I encountered an issue while testing a controller that relies on a service. The problem arises because the service is currently set to null in order to focus solely on testing the controller.

The current test setup is failing due to the BoardService being null.

beforeEach(inject(function($rootScope, $controller) {

    scope = $rootScope.$new();

    BoardController = $controller('BoardController', { 
        $scope: scope,
        board: {id: 1, tasks: {}},
        BoardService: null
    });

}));


it ("should add a new task", function() {

    var tasksBefore = scope.board.tasks.length;

    scope.addTask(category, 'this is a new task');

    var tasksAfter = scope.board.tasks.length;

    expect(tasksAfter).toBe(tasksBefore + 1);
});

This is the addTask() function defined in the controller:

$scope.addTask = function(category, task) {

    BoardService.addTask({name : task, category : category.id}).success(function(task_id) {
        // Removed code for simplicity
    });

}

Lastly, here is the corresponding function within the service:

this.addTask = function(data) {
    return $http.post($rootScope.serverRoot + '/task/create', data);            
}

javascript angularjs unit-testing testing jasmine

Answer 1

Answer №1

It seems like the intention here is to create a jest of a BroadService, so how about trying something along these lines...

beforeEach(inject(function($rootScope, $controller) {

    scope = $rootScope.$new();
    var boardService = {
         addTask:function(task){
            var d = $q.defer();
            d.resolve(/*You can return an integer or anything else that your service function returns */);
            return d.promise;
         };
    };

    BoardController = $controller('BoardController', { 
        $scope: scope,
        board: {id: 1, tasks: {}},
        BoardService: boardService
    });

}));


it ("should add a new task", function() {

    var tasksBefore = scope.board.tasks.length;

    scope.addTask(category, 'this is a new task');
    scope.$apply();
    var tasksAfter = scope.board.tasks.length;

    expect(tasksAfter).toBe(tasksBefore + 1);
});

Answer 2

It seems like the intention here is to create a jest of a BroadService, so how about trying something along these lines...

beforeEach(inject(function($rootScope, $controller) {

    scope = $rootScope.$new();
    var boardService = {
         addTask:function(task){
            var d = $q.defer();
            d.resolve(/*You can return an integer or anything else that your service function returns */);
            return d.promise;
         };
    };

    BoardController = $controller('BoardController', { 
        $scope: scope,
        board: {id: 1, tasks: {}},
        BoardService: boardService
    });

}));


it ("should add a new task", function() {

    var tasksBefore = scope.board.tasks.length;

    scope.addTask(category, 'this is a new task');
    scope.$apply();
    var tasksAfter = scope.board.tasks.length;

    expect(tasksAfter).toBe(tasksBefore + 1);
});

Answer 3

Answer №2

To start, you must simulate the BoardService and create a placeholder for the function that needs to be tested.

beforeEach(inject(function ($rootScope, $controller, $q) {
    fakeDashboardItemService = {
        addTask: function () {}
    };

    scope = $rootScope.$new();
    q = $q;
    BoardController = $controller('BoardController', {
        $scope: scope, 
        BoardService: fakeBoardService
    });
}));

Next, use spyOn on the stubbed function, define your test scenario, and return the promise. Using $digest helps with speed and prevents interference with the root scope ($apply vs $digest in directive testing)

it ("should add a new task", function() {
    spyOn(fakeBoardService, 'addTask').andCallFake(function () {
        var deferred = q.defer();
        deferred.resolve(/*return test case here*/);
        return deferred.promise;
    })

    var tasksBefore = scope.board.tasks.length;
    scope.addTask(category, 'this is a new task');
    scope.$digest();
    var tasksAfter = scope.board.tasks.length;
    expect(tasksAfter).toBe(tasksBefore + 1);
});

An important step is to refactor your controller method to utilize .then instead of .success. and .error. This allows you to handle the entire $http promise and not just specific success and error functions that may not trigger when returning the promise from your test function. Keep in mind that .then provides the full response, not just the data.

$scope.addTask = function(category, task) {
    BoardService.addTask({name: task, category: category.id}).then(function(response) {
        // handle success case
        var task_id = response.data;
    }, function(err) {
        // handle error case
    });
}

Answer 4

To start, you must simulate the BoardService and create a placeholder for the function that needs to be tested.

beforeEach(inject(function ($rootScope, $controller, $q) {
    fakeDashboardItemService = {
        addTask: function () {}
    };

    scope = $rootScope.$new();
    q = $q;
    BoardController = $controller('BoardController', {
        $scope: scope, 
        BoardService: fakeBoardService
    });
}));

Next, use spyOn on the stubbed function, define your test scenario, and return the promise. Using $digest helps with speed and prevents interference with the root scope ($apply vs $digest in directive testing)

it ("should add a new task", function() {
    spyOn(fakeBoardService, 'addTask').andCallFake(function () {
        var deferred = q.defer();
        deferred.resolve(/*return test case here*/);
        return deferred.promise;
    })

    var tasksBefore = scope.board.tasks.length;
    scope.addTask(category, 'this is a new task');
    scope.$digest();
    var tasksAfter = scope.board.tasks.length;
    expect(tasksAfter).toBe(tasksBefore + 1);
});

An important step is to refactor your controller method to utilize .then instead of .success. and .error. This allows you to handle the entire $http promise and not just specific success and error functions that may not trigger when returning the promise from your test function. Keep in mind that .then provides the full response, not just the data.

$scope.addTask = function(category, task) {
    BoardService.addTask({name: task, category: category.id}).then(function(response) {
        // handle success case
        var task_id = response.data;
    }, function(err) {
        // handle error case
    });
}

Exploring AngularJS and Jasmine: Testing a controller function that interacts with a service via $http

Answer №1

Answer №2

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