defineSuite([
        'Widgets/VRButton/VRButtonViewModel',
        'Core/Fullscreen',
        'Specs/createScene'
    ], function(
        VRButtonViewModel,
        Fullscreen,
        createScene) {
    'use strict';

    var scene;

    beforeEach(function() {
        scene = createScene();
    });

    afterEach(function() {
        scene.destroyForSpecs();
    });

    it('constructor sets default values', function() {
        var viewModel = new VRButtonViewModel(scene);
        expect(viewModel.vrElement).toBe(document.body);
        expect(viewModel.isDestroyed()).toEqual(false);
        viewModel.destroy();
        expect(viewModel.isDestroyed()).toEqual(true);
    });

    it('constructor sets expected values', function() {
        var testElement = document.createElement('span');
        var viewModel = new VRButtonViewModel(scene, testElement);
        expect(viewModel.vrElement).toBe(testElement);
        viewModel.destroy();
    });

    it('constructor can take an element id', function() {
        var testElement = document.createElement('span');
        testElement.id = 'testElement';
        document.body.appendChild(testElement);
        var viewModel = new VRButtonViewModel(scene, 'testElement');
        expect(viewModel.vrElement).toBe(testElement);
        viewModel.destroy();
        document.body.removeChild(testElement);
    });

    it('isVREnabled work as expected', function() {
        var viewModel = new VRButtonViewModel(scene);
        expect(viewModel.isVREnabled).toEqual(Fullscreen.enabled);
        viewModel.isVREnabled = false;
        expect(viewModel.isVREnabled).toEqual(false);
        viewModel.destroy();
    });

    it('can get and set vrElement', function() {
        var testElement = document.createElement('span');
        var viewModel = new VRButtonViewModel(scene);
        expect(viewModel.vrElement).not.toBe(testElement);
        viewModel.vrElement = testElement;
        expect(viewModel.vrElement).toBe(testElement);
    });

    it('throws when constructed without a scene', function() {
        expect(function() {
            return new VRButtonViewModel();
        }).toThrowDeveloperError();
    });

    it('throws is setting vrElement is not an Element', function() {
        var viewModel = new VRButtonViewModel(scene);
        expect(function() {
            viewModel.vrElement = {};
        }).toThrowDeveloperError();
    });
});