Updated the test system

test/omit.test.js

@@ -0,0 +1,9 @@
+const expect = require('expect');
+const {omit} = require('./_30s.js');
+
+test('omit is a Function', () => {
+  expect(omit).toBeInstanceOf(Function);
+});
+test('Omits the key-value pairs corresponding to the given keys from an object', () => {
+  expect(omit({ a: 1, b: '2', c: 3 }, ['b'])).toEqual({ a: 1, c: 3 });
+});