Edit in JSFiddle

var Gallery = Backbone.Model.extend({
    timeout: 3000,
    setTimeout: function(num) {
        this.timeout = num;
    }
});

var myGallery = new Gallery();
myGallery.setTimeout(5000);

var otherGallery = new Gallery();
otherGallery.setTimeout(1000);

describe('myGallery', function() {
    it('should have it\'s own timeout property', function() {
        expect(myGallery.hasOwnProperty('timeout')).toBe(true);
    });
    it('should NOT have it\'s own setTimeout property', function() {
        expect(myGallery.hasOwnProperty('setTimeout')).toBe(false);
    });
    it('should have a timeout of 5000', function() {
        expect(myGallery.timeout).toEqual(5000);
    });
});

describe('otherGallery', function() {
    it('should have it\'s own timeout property', function() {
        expect(myGallery.hasOwnProperty('timeout')).toBe(true);
    });
    it('should NOT have it\'s own setTimeout property', function() {
        expect(myGallery.hasOwnProperty('setTimeout')).toBe(false);
    });    
    it('should have a timeout of 1000', function() {
        expect(otherGallery.timeout).toEqual(1000);
    });
});