text: const expect = require('expect');
  const {atob} = require('./_30s.js');
  
  test('atob is a Function', () => {
    expect(atob).toBeInstanceOf(Function);
  });
  test('atob("Zm9vYmFy") equals "foobar"', () => {
    expect(atob('Zm9vYmFy')).toBe('foobar');
  });
  test('atob("Z") returns ""', () => {
    expect(atob('Z')).toBe('');
  });
  