Updated the test system

test/tomorrow.test.js

@@ -0,0 +1,17 @@
+const expect = require('expect');
+const {tomorrow} = require('./_30s.js');
+
+test('tomorrow is a Function', () => {
+  expect(tomorrow).toBeInstanceOf(Function);
+});
+const t1 = new Date(new Date().getFullYear(), new Date().getMonth(), new Date().getDate() + 1);
+const t2 = new Date(tomorrow());
+test('Returns the correct year', () => {
+  expect(t1.getFullYear()).toBe(t2.getFullYear());
+});
+test('Returns the correct month', () => {
+  expect(t1.getMonth()).toBe(t2.getMonth());
+});
+test('Returns the correct date', () => {
+  expect(t1.getDate()).toBe(t2.getDate());
+});