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


  test('permutations is a Function', () => {
  expect(permutations).toBeInstanceOf(Function);
});
  t.deepEqual(permutations([1, 33, 5]), [ [ 1, 33, 5 ], [ 1, 5, 33 ], [ 33, 1, 5 ], [ 33, 5, 1 ], [ 5, 1, 33 ], [ 5, 33, 1 ] ], 'Generates all permutations of an array');