Updated the test system

test/escapeHTML.test.js

@@ -0,0 +1,11 @@
+const expect = require('expect');
+const {escapeHTML} = require('./_30s.js');
+
+test('escapeHTML is a Function', () => {
+  expect(escapeHTML).toBeInstanceOf(Function);
+});
+test('Escapes a string for use in HTML', () => {
+  expect(escapeHTML('<a href="#">Me & you</a>')).toBe(
+    '&lt;a href=&quot;#&quot;&gt;Me &amp; you&lt;/a&gt;'
+  );
+});