使用sinon.js创建一个基于真实构造函数/原型的间谍方法的“间谍对象”

I'm using sinon.js as a way to stub out dependencies in my Mocha tests. I prefer the 'spy' approach over a classic mock approach, as the introspection of the spy seems clearer and affords more flexibility than the somewhat backward-thinking with classic mock objects.I'm using sinon.js as a way to stub out depende