Migrated tests to jest

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

test4/objectFromPairs/objectFromPairs.js

@@ -0,0 +1,2 @@
+const objectFromPairs = arr => arr.reduce((a, v) => ((a[v[0]] = v[1]), a), {});
+module.exports = objectFromPairs;

test4/objectFromPairs/objectFromPairs.test.js

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