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


  test('tail is a Function', () => {
  expect(tail).toBeInstanceOf(Function);
});
  test('Returns tail', () => {
  expect(tail([1, 2, 3]), [2).toEqual(3])
});
  test('Returns tail', () => {
  expect(tail([1])).toEqual([1])
});