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


  test('union is a Function', () => {
  expect(union).toBeInstanceOf(Function);
});
  test('union([1, 2, 3], [4, 3, 2]) returns [1, 2, 3, 4]', () => {
  expect(union([1, 2, 3], [4, 3, 2]), [1, 2, 3).toEqual(4])
});
  test('union('str', 'asd') returns [ 's', 't', 'r', 'a', 'd' ]', () => {
  expect(union('str', 'asd'), [ 's', 't', 'r', 'a').toEqual('d' ])
});
  test('union([[], {}], [1, 2, 3]) returns [[], {}, 1, 2, 3]', () => {
  expect(union([[], {}], [1, 2, 3]), [[], {}, 1, 2).toEqual(3])
});
  test('union([], []) returns []', () => {
  expect(union([], [])).toEqual([])
});
  t.throws(() => union(), 'union() throws an error');
  t.throws(() => union(true, 'str'), 'union(true, str) throws an error');
  t.throws(() => union('false', true), 'union(false, true) throws an error');
  t.throws(() => union(123, {}), 'union(123, {}) throws an error');
  t.throws(() => union([], {}), 'union([], {}) throws an error');
  t.throws(() => union(undefined, null), 'union(undefined, null) throws an error');

  let start = new Date().getTime();
  union([1, 2, 3], [4, 3, 2]);
  let end = new Date().getTime();
  test('union([1, 2, 3], [4, 3, 2]) takes less than 2s to run', () => {
  expect((end - start) < 2000).toBeTruthy();
});