Migrated tests to jest

Used jest-codemods to migrate, will have to pass everything by hand before we can merge.

test4/mapObject/mapObject.js

@@ -0,0 +1,5 @@
+const mapObject = (arr, fn) =>
+(a => (
+(a = [arr, arr.map(fn)]), a[0].reduce((acc, val, ind) => ((acc[val] = a[1][ind]), acc), {})
+))();
+module.exports = mapObject;

test4/mapObject/mapObject.test.js

@@ -0,0 +1,11 @@
+const expect = require('expect');
+const mapObject = require('./mapObject.js');
+
+test('Testing mapObject', () => {
+  //For more information on all the methods supported by tape
+  //Please go to https://github.com/substack/tape
+  expect(typeof mapObject === 'function').toBeTruthy();
+  expect(mapObject([1, 2, 3], a => a * a)).toEqual({ 1: 1, 2: 4, 3: 9 });
+  expect(mapObject([1, 2, 3, 4], (a, b) => b - a)).toEqual({ 1: -1, 2: -1, 3: -1, 4: -1 });
+  expect(mapObject([1, 2, 3, 4], (a, b) => a - b)).toEqual({ 1: 1, 2: 1, 3: 1, 4: 1 });
+});