Why?

why jest, why.js

describe('Jest', ()=> {
    it('what', (done)=> {
        Promise.resolve().then(()=> {
            throw new Error('ya yaya');
        }).then(done, done);
    })

    it('okay', ()=> {
        return Promise.resolve().then(()=> {
            throw new Error('ya yaya');
        });
    })

    it('well, really', (done)=> {
        done(new Error('aaaa'));
    });
});