const expect = require('expect');
const nthArg = require('./nthArg.js');


  test('nthArg is a Function', () => {
  expect(nthArg).toBeInstanceOf(Function);
});
  const third = nthArg(2);
  test('Returns the nth argument', () => {
  expect(third(1, 2, 3), 3).toBe()
});
  test('Returns undefined if arguments too few', () => {
  expect(third(1, 2), undefined).toBe()
});
  const last = nthArg(-1);
  test('Works for negative values', () => {
  expect(last(1, 2, 3, 4, 5), 5).toBe()
});