const {nest} = require('./_30s.js');

test('nest is a Function', () => {
  expect(nest).toBeInstanceOf(Function);
});
test('Nests items', () => {
  const comments = [
    { id: 1, parent_id: null },
    { id: 2, parent_id: 1 },
    { id: 3, parent_id: 1 },
    { id: 4, parent_id: 2 },
    { id: 5, parent_id: 4 }
  ];
  expect(nest(comments)).toEqual([{ 'id': 1, 'parent_id': null, 'children': [{ 'id': 2, 'parent_id': 1, 'children': [{ 'id': 4, 'parent_id': 2, 'children': [{ 'id': 5, 'parent_id': 4, 'children': [] }] }] }, { 'id': 3, 'parent_id': 1, 'children': [] }] }]);
});