sinon_constructor_test_example.js

//Your example Class
function Person(name) {
	this.name = name;
}

Person.prototype.greet = function () {
	alert(this.name);
};

//The code using the class you want to test
function GreetCjno() {
	var person = new Person('cjno');
	person.greet();
}

//The actual test for JST
TestCase('ExampleTest', sinon.testCase({
	'test that cjno gets greeted': function () {
		Person = this.spy(Person);
		this.spy(Person.prototype, 'greet');

		GreetCjno();

		Person.alwaysCalledWithExactly('cjno');
		assertTrue(Person.prototype.greet.calledOnce);
	}
}));