const {mapString} = require('./_30s.js'); test('mapString is a Function', () => { expect(mapString).toBeInstanceOf(Function); }); test('mapString returns a capitalized string', () => { expect(mapString('test', c => c.toUpperCase())).toBe('TEST'); }); const indexMapper = (c, i) => `${c}[${i}]`; test('mapString can deal with indexes', () => { expect(mapString('test', indexMapper)).toBe('t[0]e[1]s[2]t[3]'); }); const fullStringMapper = (c, i, str) => `{${str}}${c}[${i}]`; test('mapString can deal with the full string', () => { expect(mapString('test', fullStringMapper)).toBe('{test}t[0]{test}e[1]{test}s[2]{test}t[3]'); });