Migrated tests to jest

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

test3/invertKeyValues/invertKeyValues.test.js

@@ -0,0 +1,10 @@
+const expect = require('expect');
+const invertKeyValues = require('./invertKeyValues.js');
+
+test('Testing invertKeyValues', () => {
+  //For more information on all the methods supported by tape
+  //Please go to https://github.com/substack/tape
+  expect(typeof invertKeyValues === 'function').toBeTruthy();
+  expect(invertKeyValues({ a: 1, b: 2, c: 1 })).toEqual({ 1: [ 'a', 'c' ], 2: [ 'b' ] });
+  expect(invertKeyValues({ a: 1, b: 2, c: 1 }, value => 'group' + value)).toEqual({ group1: [ 'a', 'c' ], group2: [ 'b' ] });
+});