const expect = require('expect'); const {sortedIndexBy} = require('./_30s.js'); test('sortedIndexBy is a Function', () => { expect(sortedIndexBy).toBeInstanceOf(Function); }); test('Returns the lowest index to insert the element without messing up the list order', () => { expect(sortedIndexBy([{ x: 4 }, { x: 5 }], { x: 4 }, o => o.x)).toBe(0); }); test('Returns the lowest index to insert the element without messing up the list order', () => { expect(sortedIndexBy([{ x: 5 }, { x: 4 }], { x: 4 }, o => o.x)).toBe(1); }); test('Returns the lowest index to insert the element without messing up the list order', () => { expect(sortedIndexBy([{ x: 4 }, { x: 5 }], { x: 6 }, o => o.x)).toBe(2); });