const expect = require('expect'); const converge = require('./converge.js'); test('converge is a Function', () => { expect(converge).toBeInstanceOf(Function); }); const average = converge((a, b) => a / b, [ arr => arr.reduce((a, v) => a + v, 0), arr => arr.length, ]); test('Produces the average of the array', () => { expect(average([1, 2, 3, 4, 5, 6, 7])).toBe(4); }); const strangeConcat = converge((a, b) => a + b, [ x => x.toUpperCase(), x => x.toLowerCase()] ); test('Produces the strange concatenation', () => { expect(strangeConcat('Yodel')).toBe('YODELyodel'); });