Updated the test system

test/objectFromPairs.test.js

@@ -0,0 +1,9 @@
+const expect = require('expect');
+const {objectFromPairs} = require('./_30s.js');
+
+test('objectFromPairs is a Function', () => {
+  expect(objectFromPairs).toBeInstanceOf(Function);
+});
+test('Creates an object from the given key-value pairs.', () => {
+  expect(objectFromPairs([['a', 1], ['b', 2]])).toEqual({ a: 1, b: 2 });
+});