function doSomethingAsyncThatIsInaccessible(cb) {
    new Promise(resolve => {
        cb();
        resolve();
    });
}
 
describe('Some Test', () => {
    beforeEach(() => {
        PromiseSpy.install();
    });
    afterEach(() => {
        PromiseSpy.uninstall();
    });
 
    it('should do something', async () => {
        const callback = sinon.stub();
        doSomethingAsyncThatIsInaccessible(callback);
 
        await PromiseSpy.wait();
 
        expect(callback.calledOnce).to.equal(true);
    });
});