Update

MOCHA/operations.js

@@ -0,0 +1,12 @@
+module.exports.multiply = function (x, y) {
+    return x * y;
+};
+module.exports.add = function (x, y) {
+    return x + y;
+};
+
+module.exports.multiplyAsync = function (a, b, callback) {
+    setTimeout(function () {
+        callback(a * b);
+    }, 1000);
+};

MOCHA/operations.test.js

@@ -0,0 +1,32 @@
+var operations = require('./operations');
+
+it('should multiply two numbers', function () {
+    var expectedResult = 15;
+    var result = operations.multiply(3, 5);
+    if (result !== expectedResult) {
+        throw new Error(
+            `Expected ${expectedResult}, but got ${result}`
+        );
+    }
+});
+it('should add two numbers', function () {
+    var expectedResult = 16;
+    var result = operations.add(9, 7);
+    if (result !== expectedResult) {
+        throw new Error(
+            `Expected ${expectedResult}, but got ${result}`
+        );
+    }
+});
+
+it('shoud async multiply two numbers', function (done) {
+    var expectedResult = 12;
+    operations.multiplyAsync(4, 3, function (result) {
+        if (result !== expectedResult) {
+            throw new Error(
+                `Expected ${expectedResult}, but got ${result}`
+            );
+        }
+        done();
+    });
+});

MOCHA/package.json

@@ -0,0 +1,10 @@
+{
+    "name": "testapp",
+    "version": "1.0.0",
+    "scripts": {
+        "test": "mocha *.test.js"
+    },
+    "devDependencies": {
+        "mocha": "^3.2.0"
+    }
+}