Jasmine.Async example

Calculator.js

var Calculator = function(displayElement) {
	this.$el = $(displayElement);
};

Calculator.prototype.hideResult = function(cb) {
	this.$el.fadeOut(1000, cb);
};

CalculatorSpec.js

describe("Calculator", function() {
	var calc, el;
	var async = new AsyncSpec(this);

	beforeEach(function() {
		el = $("<div>some content</div>");
		$("#container").append(el);
		calc = new Calculator(el);
	});
	
	afterEach(function() {
		el.remove();
	});

	async.it("should make the result invisible", function(done) {
		var callback = function() {
			expect(el.css("display")).toBe("none");
			done();
		};
		  
		calc.hideResult(callback);
	});
});