Updated the test system

test/orderBy.test.js

@@ -0,0 +1,21 @@
+const expect = require('expect');
+const {orderBy} = require('./_30s.js');
+
+test('orderBy is a Function', () => {
+  expect(orderBy).toBeInstanceOf(Function);
+});
+const users = [{ name: 'fred', age: 48 }, { name: 'barney', age: 36 }, { name: 'fred', age: 40 }];
+test('Returns a sorted array of objects ordered by properties and orders.', () => {
+  expect(orderBy(users, ['name', 'age'], ['asc', 'desc'])).toEqual([
+    { name: 'barney', age: 36 },
+    { name: 'fred', age: 48 },
+    { name: 'fred', age: 40 }
+  ]);
+});
+test('Returns a sorted array of objects ordered by properties and orders.', () => {
+  expect(orderBy(users, ['name', 'age'])).toEqual([
+    { name: 'barney', age: 36 },
+    { name: 'fred', age: 40 },
+    { name: 'fred', age: 48 }
+  ]);
+});