How do I stub new Date() using sinon?
I suspect you want the useFakeTimers function: var now = new Date(); var clock = sinon.useFakeTimers(now.getTime()); //assertions clock.restore(); This is plain JS. A working TypeScript/JavaScript example: var now = new Date(); beforeEach(() => { sandbox = sinon.sandbox.create(); clock = sinon.useFakeTimers(now.getTime()); }); afterEach(() => { sandbox.restore(); clock.restore(); });