spy.on doesn't work with nullish prototype

[sebamarynissen]

I've noticed that if you do something like

const object = Object.create(null);
object.method = function() {};
chai.spy.on(object, 'method');

it will throw an error because it uses

object.hasOwnProperty(methodName);

This can be fixed easily by changing it to

Object.hasOwnProperty.call(object, methodName);

I will file a PR for this.

Context

I've encountered the issue in the context of migrating to Vue 3 and using @vue/test-utils. Apparently if you mount a component like

import { mount } from '@vue/test-utils';
let { vm } = mount(Component);

then vm is an object with null as its prototype. If you then want to spy on some of its methods with chai.spy.on, it throws the error above.