export default function myBind(fn, thisArg, ...boundArgs) {
  throw new Error('Not implemented');
}

import myBind from './file';

describe('myBind', () => {
  test('binds this for normal calls', () => {
    function getX() { return this.x; }
    const obj = { x: 42 };
    const bound = myBind(getX, obj);
    expect(bound()).toBe(42);
  });

  test('supports partial application', () => {
    function add(a, b, c) { return a + b + c; }
    const add5 = myBind(add, null, 2, 3);
    expect(add5(10)).toBe(15);
  });

  test('when called with new, ignores thisArg and uses the new instance', () => {
    function Person(name) { this.name = name; }
    Person.prototype.say = function() { return this.name; };

    const BoundPerson = myBind(Person, { name: 'SHOULD_NOT_USE' });
    const p = new BoundPerson('Ada');

    expect(p.name).toBe('Ada');
    expect(p.say()).toBe('Ada');
  });

  test('instances created via new boundFn() are instanceof original fn', () => {
    function Person(name) { this.name = name; }
    const BoundPerson = myBind(Person, { name: 'X' });
    const p = new BoundPerson('Ada');

    expect(p instanceof Person).toBe(true);
    expect(p instanceof BoundPerson).toBe(true);
  });

  test('constructor return object behavior is preserved', () => {
    function Factory(name) { this.name = name; return { ok: true, name }; }
    const BoundFactory = myBind(Factory, { name: 'X' });
    const res = new BoundFactory('Ada');

    expect(res).toEqual({ ok: true, name: 'Ada' });
  });
});