6. Testing Node.js Applications | Learning Node.js for .NET Developers

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Table Of Contents

Learning Node.js for .NET Developers

By : Cummings

4 (2)

Learning Node.js for .NET Developers

4 (2)

By: Cummings

Overview of this book

Node.js is an open source, cross-platform runtime environment that allows you to use JavaScript to develop server-side web applications. This short guide will help you develop applications using JavaScript and Node.js, leverage your existing programming skills from .NET or Java, and make the most of these other platforms through understanding the Node.js programming model. You will learn how to build web applications and APIs in Node, discover packages in the Node.js ecosystem, test and deploy your Node.js code, and more. Finally, you will discover how to integrate Node.js and .NET code.

Preface

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Free Chapter

1. Why Node.js?

1. Why Node.js?

What is Node.js?

Why JavaScript?

When to use Node.js

Summary

2. Getting Started with Node.js

2. Getting Started with Node.js

Installing and running Node.js

Choosing an editor

Using an application framework

Summary

3. A JavaScript Primer

3. A JavaScript Primer

Introducing JavaScript types

Functional object-oriented programming

Summary

4. Introducing Node.js Modules

4. Introducing Node.js Modules

Organizing your codebase

Creating modules in Node.js

Defining a directory-level module

Implementing an Express middleware module

Summary

5. Creating Dynamic Websites

5. Creating Dynamic Websites

Handling user-submitted data

Communicating via Ajax

Implementing other data operations

Summary

6. Testing Node.js Applications

6. Testing Node.js Applications

Writing a simple test in Node.js

Structuring the codebase for tests

Writing BDD-style tests with Mocha

Using Chai for assertions

Creating test doubles

Testing an Express application

Full-stack testing with PhantomJS

Summary

7. Setting up an Automated Build

7. Setting up an Automated Build

Setting up an integration server

Automating the build process with Gulp

Checking code style with ESLint

Gathering code coverage statistics

Running integration tests from Gulp

Summary

8. Mastering Asynchronicity

8. Mastering Asynchronicity

Using the callback pattern for asynchronous code

Writing cleaner asynchronous code using promises

Combining asynchronous programming patterns

Summary

9. Persisting Data

9. Persisting Data

Introducing MongoDB

Using MongoDB with Express

Introducing Redis

Building a user ranking system with Redis

A note on security

Summary

10. Creating Real-time Web Apps

10. Creating Real-time Web Apps

Understanding options for real-time communication

Introducing Socket.IO

Scaling real-time Node.js applications

Integrating Socket.IO with Express

Directing Socket.IO messages

Testing Socket.IO applications

Organizing Socket.IO applications

Summary

11. Deploying Node.js Applications

11. Deploying Node.js Applications

Working with Heroku

Deploying from Travis CI

Further resources

Summary

12. Authentication in Node.js

12. Authentication in Node.js

Introducing Passport

Using Express sessions

Implementing social login

Allowing users to log out

Adding other login providers

Summary

13. Creating JavaScript Packages

13. Creating JavaScript Packages

Writing universal modules

Writing npm packages

Publishing a package to npm

Using Node.js modules in the browser

Summary

14. Node.js and Beyond

14. Node.js and Beyond

Understanding Node.js versioning

Understanding ECMAScript versioning

Exploring ECMAScript 2015

Introducing ECMAScript 2016

Going beyond JavaScript

JavaScript and ASP.NET

Summary

Index

Index

Creating test doubles

There are more tests we could write for the games service, but let's look at a different module for now. How would we go about testing our users middleware? The following code is from middleware/users.js:

module.exports = function(req, res, next) {
    let userId = req.cookies.userId;
    if (!userId) {
        userId = uuid.v4();
        res.cookie('userId', userId);
    }
    req.user = {
        id: userId
    };
    next();
};

In order to test this class, we will need to pass in arguments for the req, res, and next parameters with which our code interacts. We don't have a real request, response, or middleware pipeline available, so we need to create some stand-in values instead. Stand-in values such as this are generally called test doubles. Our code reads an attribute from the request and calls the cookie method on the response. We can create test doubles for these as follows, in a new test script under test/middleware/users.js:

'use strict';

const middleware = require...

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