Mocha + Sinon + Expect.js

gistfile1.js

describe('addHandler', function() {
	it('parses request and calls api', function() {
		var values = {
			link: 'link' + Math.floor(Math.random() * 1000),
			user: 'user' + Math.floor(Math.random() * 1000),
			seconds: Math.floor(Math.random() * 1000)
		};

		// setup
		var impressionsMock = sinon.mock(impressions);
		impressionsMock.expects('add', function(db, user, link, facts, callback) {
			expect(db).to.be.ok();
			expect(user).to.eql(values.user);
			expect(link).to.eql(values.link);
			expect(facts).to.be.ok();
			expect(facts).to.have.property('seconds', values.seconds);
			expect(typeof callback).to.be('function');
			callback();
		});

		var res = {
			end: sinon.stub()
		};

		var req = {
			session: { user: { _id: values.user } },
			body: { link: values.link, seconds: values.seconds }
		};

		// test
		impressions.addHandler(req, res);

		// verify
		expect(res.end.calledOnce);
		impressionsMock.verify();
		impressionsMock.restore();
	});
});