[backend][nodejs] Add sample test

backend/nodejs/package.json

@@ -4,7 +4,7 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "mocha"
   },
   "keywords": [],
   "author": "",

backend/nodejs/test/test.js

@@ -0,0 +1,9 @@
+var assert = require('assert');
+
+describe('Array', function () {
+    describe('#indexOf', function () {
+        it('should return -1 when the value is not present', function () {
+            assert.strictEqual([1, 2, 3].indexOf(4), -1);
+        });
+    })
+})