Updated the test system

test/sleep.test.js

@@ -0,0 +1,12 @@
+const expect = require('expect');
+const {sleep} = require('./_30s.js');
+
+test('sleep is a Function', () => {
+  expect(sleep).toBeInstanceOf(Function);
+});
+test('Works as expected', () => {
+  async function sleepyWork() {
+    await sleep(1000);
+    expect(true).toBeTruthy();
+  }
+});