const {symmetricDifferenceWith} = require('./_30s.js'); test('symmetricDifferenceWith is a Function', () => { expect(symmetricDifferenceWith).toBeInstanceOf(Function); }); test('Returns the symmetric difference between two arrays, using a provided function as a comparator', () => { expect( symmetricDifferenceWith( [1, 1.2, 1.5, 3, 0], [1.9, 3, 0, 3.9], (a, b) => Math.round(a) === Math.round(b) ) ).toEqual([1, 1.2, 3.9]); });