const expect = require('expect'); const reduceWhich = require('./reduceWhich.js'); test('reduceWhich is a Function', () => { expect(reduceWhich).toBeInstanceOf(Function); }); test('Returns the minimum of an array', () => { expect(reduceWhich([1, 3, 2])).toBe(1); }); test('Returns the maximum of an array', () => { expect(reduceWhich([1, 3, 2], (a, b) => b - a)).toBe(3); }); test('Returns the object with the minimum specified value in an array', () => { expect(reduceWhich( [{ name: 'Tom', age: 12 }, { name: 'Jack', age: 18 }, { name: 'Lucy', age: 9 }], (a, b) => a.age - b.age )).toEqual({name: "Lucy", age: 9}); });