text: const {ary} = require('./_30s.js');
  
  test('ary is a Function', () => {
    expect(ary).toBeInstanceOf(Function);
  });
  const firstTwoMax = ary(Math.max, 2);
  test('Discards arguments with index >=n', () => {
    expect([[2, 6, 'a'], [6, 4, 8], [10]].map(x => firstTwoMax(...x))).toEqual([6, 6, 10]);
  });
  