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

test('findLastKey is a Function', () => {
  expect(findLastKey).toBeInstanceOf(Function);
});
test('returns the appropriate key', () => {
  expect(
    findLastKey(
      {
        barney: { age: 36, active: true },
        fred: { age: 40, active: false },
        pebbles: { age: 1, active: true }
      },
      o => o['active']
    )
  ).toBe('pebbles');
});