Updated the test system

test/palindrome.test.js

@@ -0,0 +1,12 @@
+const expect = require('expect');
+const {palindrome} = require('./_30s.js');
+
+test('palindrome is a Function', () => {
+  expect(palindrome).toBeInstanceOf(Function);
+});
+test('Given string is a palindrome', () => {
+  expect(palindrome('taco cat')).toBeTruthy();
+});
+test('Given string is not a palindrome', () => {
+  expect(palindrome('foobar')).toBeFalsy();
+});