Updated the test system

test/forOwn.test.js

@@ -0,0 +1,11 @@
+const expect = require('expect');
+const {forOwn} = require('./_30s.js');
+
+test('forOwn is a Function', () => {
+  expect(forOwn).toBeInstanceOf(Function);
+});
+let output = [];
+forOwn({ foo: 'bar', a: 1 }, v => output.push(v));
+test("Iterates over an element's key-value pairs", () => {
+  expect(output).toEqual(['bar', 1]);
+});