What are Sinon spies and how do I use them?

What are Sinon spies and how do I use them?

Sinon spies are functions that allow you to track calls to other functions in your code. They can be used to verify that a function was called, how many times it was called, and with what arguments.

Can you give me an example of how to create a Sinon spy?

Sure! You can create a Sinon spy like this: const mySpy = sinon.spy(); Then, you can call mySpy() and check its behavior.

How do I assert that the spy was called?

You can use sinon.assert.called(mySpy); to assert that the spy was called at least once.

What if I want to check the arguments it was called with?

You can use sinon.assert.calledWith(mySpy, arg1, arg2); to check if the spy was called with specific arguments.