The problem I'm seeing in your code is that expect().toThrowError() expects an synchronous exception, but your code is actually rejecting a promise. The bit that may be confusing is that you see throw new Error('foo'); in your handleResponse. That's throwing an exception, true. However, because this code is called by an async function this exception is converted to a promise rejection. So await get('sampleUrl') does not result in a synchronous exception being thrown but in an asynchronous promise rejection.

Looking at Jest's documentation, it seems to me that you should be doing:

return expect(expectedError()).rejects.toThrowError();

You need to call expectedError because it is a function that returns a promise, and you need to use .rejects to converts the rejection to a plain exception that can be tested with .toThrowError(). Make sure to return the assertion, or await it. Otherwise you'll have dangling promise.

Note: This answer is now outdated, see this answer by Laszlo Sarvold instead.

axios-mock-adapter does not appear to have this functionality built in to it, however if you are using jest, you can use jest.spyOn.

For your example above

let spy = jest.spyOn(axios, "get");
//run http request here
expect(spy).toHaveBeenCalled();

Note: depending on what you are using, you may have to wrap your expect statement in setTimeout(function, 0) for it to work properly