Interface SpyBehavior

import { spy } from '@paychex/core';

const method = spy().invokes(function(...args) {
  console.log('method called with', args);
});

method.onCall(1).invokes(function(...args) {
  console.log('method called 2nd time', args);
});

import { spy } from '@paychex/core';

const method = spy().returns('abc');

method.onCall(1).returns('def');

import { spy } from '@paychex/core';

const method = spy().throws(new Error());

method.onCall(1).throws(new Error('2nd call'));