Updated the test system

test/debounce.test.js

@@ -0,0 +1,11 @@
+const expect = require('expect');
+const {debounce} = require('./_30s.js');
+
+test('debounce is a Function', () => {
+  expect(debounce).toBeInstanceOf(Function);
+});
+test('Works as expected', () => {
+  debounce(() => {
+    expect(true).toBeTruthy();
+  });
+});