Mastering Angular Test-Driven Development E-Book

Ezéchiel Amen AGBLA

• Herausgeber: Packt Publishing
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 247

Veröffentlichungsjahr: 2024

Beschreibung

Do you want to learn how to build robust, reliable, and impressive Angular applications? If yes, then Angular test-driven development is for you!
Mastering Angular Test-Driven Development is a comprehensive guide that provides you with essential resources to enhance your skills and deliver high-quality Angular applications. With a practical approach and real-world examples, the book extensively covers TDD concepts, techniques, and tools, going beyond unit testing to explore testing Angular pipes, forms, and reactive programming.
In this book, you’ll learn how to validate and manipulate data using pipes, test Angular forms for input validation and user interactions, and handle asynchronous operations with reactive programming. Additionally, you’ll discover end-to-end testing using Protractor, Cypress, and Playwright frameworks, gaining valuable insights into writing robust tests for web applications, navigation, element interaction, and behavior validation. You’ll also understand how to integrate TDD with CI/CD, learning best practices for automating tests, deploying Angular applications, and achieving faster feedback loops.
By the end of this book, you’ll be able to successfully implement TDD in your Angular projects with the help of practical examples, best practices, and clear explanations.

Leseprobe

Mastering Angular Test-Driven Development

Build high-quality Angular apps with step-by-step instructions and practical examples

Ezéchiel Amen AGBLA

Mastering Angular Test-Driven Development

Copyright © 2024 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing or its dealers and distributors, will be held liable for any damages caused or alleged to have been caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

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First published: August 2024

Production reference: 1090724

Published by Packt Publishing Ltd.

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ISBN 978-1-80512-608-9

www.packtpub.com

To my mother, Lamatou, my father, Daniel, my brothers, Salomon and Schadrac, and my sister, Christelle, for their sacrifices and for demonstrating the power of determination.

To my sister-in-law, Anne and my nephew, Samuel, for their unfailing support.

To Irma, my godmother, Bernadin, my godfather, and my brother, Jean-David, for their invaluable advice and presence during difficult times.

Finally, to my wife, Béatrice, for the unconditional love she gives me, for supporting me during this journey, and for always being there when I need her.

– Ezéchiel Amen AGBLA

Contributors

About the author

Ezéchiel Amen AGBLA is passionate about web and mobile development, with expertise in Angular and Ionic. A certified Ionic and Angular expert developer, he shares his knowledge through courses, articles, webinars, and training.

He uses his free time to help beginners and spread knowledge by writing articles, including via Openclassrooms, the leading online university in the French-speaking world. He also helps fellow developers on a part-time basis with code reviews, technical choices, and bug fixes.

His dedication to continuous learning and experience sharing contributes to his growth as a developer and mentor.

I’d like to thank all the people who have been close to me and supported me, especially my wife, Béatrice, my brothers, my sister, and my parents.

I’d also like to thank the team at Packt for their help and support throughout the process.

About the reviewers

Afolabi Opakunle is a seasoned software engineer with extensive experience in Angular since version 6, specializing in designing, planning, and developing frontend web solutions tailored to product and design requirements. Leveraging Angular’s modular framework, he has successfully led frontend development teams and contributed to enterprise projects for over four years, enhancing portfolio management processes.

He holds a certificate in Mobile Web Development from Google, where he gained a deep understanding of the Angular framework. His academic background includes a bachelor’s degree in city/urban, community, and regional planning from Obafemi Awolowo University, Ile-Ife, Nigeria. With over five years in the software industry, he has focused on developing financial technology and business management solutions. Collaborating closely with project managers from different parts of the world, he has successfully developed and updated modules and features for various enterprise applications.

Passionate about solving business challenges through innovative technologies, he continually explores new solutions to enhance project outcomes. In his leisure time, he enjoys discovering new restaurants in Lagos with friends and team members and indulging in the vibrant culinary scene.

Dhritiman Tamuli Saikia is an experienced software developer as well as a trainer. He mostly works on Angular, ReactJS, Node.js, and Express.js. He has also trained numerous students on MEAN and MERN stack development in the last few years.

Sanjay Khadka, hailing from Nepal, is an IT engineer with over 15 years of experience in web/mobile application development and a passion for open source technology.

He has held roles as a developer, principal software engineer, team lead, project manager, and software and solution architect. Additionally, he also has experience teaching at training institutes.

He had also been a visiting project supervisor for university students and a trainer at Nepal Electricity Authority.

His technical skills include iOS, web and mobile development, SQL, MongoDB, PHP, Node.js, JavaScript, Angular, Rust, system design, DevOps, and Agile.

He also holds certifications such as Registered Scrum Master™, Registered Product Owner™, and AWS Certified Solution Architect.

I extend my sincere gratitude to the author for crafting this wonderful book. I am also thankful to Shagun Saini and Vaibhav Ahire for their invaluable assistance throughout the process. This comprehensive guide to test-driven development (TDD) is highly commendable and I strongly recommend it to anyone interested in TDD. I am looking forward to more books from the author in the future.

Table of Contents

Preface

Part 1: Getting Started with Test-Driven Development in Angular

1

Taking Your First Steps with TDD

Technical requirements

Understanding TDD and its role in Angular

What is Angular and TDD?

The red-green-refactor cycle

Benefits of the red-green-refactor cycle

The role of TDD in Angular development

Setting up the development environment

Installing Node.js on Windows or macOS

Installing Node.js on Linux

Creating a new Angular project

Exploring different files related to writing tests

*.spec.ts files

The karma.conf.js file

The test.ts file

The tsconfig.spec.json file

The src/test.ts file

Summary

2

Using Jasmine and Karma to Test Angular Applications

Technical requirements

Mastering Jasmine’s unit testing techniques

What is Jasmine?

Writing descriptive test suites

Choosing meaningful names

Structuring test suites

Writing clear and concise test descriptions

Maintaining and updating descriptive test suites

Writing your first unit tests in an Angular project

Utilizing code coverage and test result analysis with Karma

Code coverage visualization

Summary

Part 2: Writing Effective Unit Tests

3

Writing Effective Unit Tests for Angular Components, Services, and Directives

Technical requirements

Advanced techniques for Angular unit testing – lifecycle hooks

Discovering lifecycle hooks

Practical application

Advanced techniques for Angular unit testing – Angular services

Testing service methods

Using rigorous directive testing to ensure proper rendering and functionality

Implementing color change directives

Writing tests for the colorChange directive

Summary

4

Mocking and Stubbing Dependencies in Angular Tests

Technical requirements

Monitoring and controlling dependency calls using method stubs and spies

Method stubs and spies

Injecting mocked dependencies using TestBed providers

Handling async operations and complex scenarios

Understanding asynchronous operations

Handling asynchronous operations

Emphasizing the importance of testing async operations

Summary

5

Testing Angular Pipes, Forms, and Reactive Programming

Technical requirements

Testing an Angular pipe as used in our project

Positive number to percentage string formatting test

Negative number to percentage string formatting test

Decimal number to percentage string formatting test

Non-number to percentage string formatting test

Implementing TDD for the Reactive Form in our calculator app

Writing a test for the calculator form

Implementing the user interface

Writing tests for the calculator component

Summary

Part 3: End-to-End Testing

6

Exploring End-to-End Testing with Protractor, Cypress, and Playwright

Technical requirements

Understanding E2E testing

Discovering the benefits of E2E testing

Exploring different approaches to E2E testing

Comparison between script-based testing and exploratory testing

Harnessing the power of E2E testing tools

Analyzing the benefits of E2E testing in a project

Exploring Protractor, Cypress, and Playwright for E2E testing

Protractor

Cypress

Playwright

Summary

7

Understanding Cypress and its Role in End-to-End Tests for Web Applications

Technical requirements

Discovering Cypress and its role in an Angular project

Understanding Cypress

Seamless integration with Angular

Efficient testing workflow

Real-time reloading and debugging

Setting up Cypress in our Angular project

Installing Cypress

Configuring Cypress

Writing your first E2E test

Summary

8

Writing Effective End-to-End Component Tests with Cypress

Technical requirements

Structuring E2E tests

Writing test cases

Addition context

Subtraction context

Multiplication context

Division context

Using Cypress custom commands

Summary

Part 4: Continuous Integration and Continuous Deployment for Angular Applications

9

Understanding Continuous Integration and Continuous Deployment (CI/CD)

Technical requirements

Understanding CI and CD

What is CI?

Benefits of CI for development teams

Key principles of CI implementation

What is CD?

Benefits of CD for development teams

Key principles of CD implementation

Setting up CI/CD pipelines for automating build with GitHub Actions

Step 1 – create or choose a repository and project

Step 2 – open GitHub Actions in your project repository

Step 3 – define your CI/CD workflow

Setting up CI/CD pipelines for automating tests with GitHub Actions

Setting up CI/CD pipelines for automating the deployment process with GitHub Actions

Summary

10

Best Practices and Patterns for Angular TDD

Best practices for TDD in Angular projects

Exploring patterns for implementing TDD in any Angular project

Choosing a TDD pattern for your Angular project

Summary

11

Refactoring and Improving Angular Code through TDD

Technical requirements

Refactoring Angular code with TDD

The power of the test-first approach

Benefits of TDD in refactoring

Examples in action

Choosing the right tests to write

Identifying code smells and areas for improvement in Angular applications

What are code smells?

Why should we care about code smells in Angular?

Identifying the most common code smells in Angular applications

Iterative improvement – red-green-refactor cycle for continuous code enhancement

Red – setting the stage with failing tests

Green – making the test pass with minimal code

Refactor – transforming the code with confidence

Summary

Index

Other Books You May Enjoy

Part 1: Getting Started with Test-Driven Development in Angular

In this part, you’ll get an overview of the benefits of test-driven development (TDD), the testing environment in an Angular project, writing unit tests with Jasmine, and configuring Karma.

This part has the following chapters:

Chapter 1, Taking Your First Steps with TDDChapter 2, Using Jasmine and Karma to Test Angular Applications

1

Taking Your First Steps with TDD

Test-driven development (TDD) is a software development process that’s widely used in Angular development to ensure code quality and reduce time spent debugging. By writing automated tests before writing production code, developers can ensure that their code meets the desired specifications and can be easily modified and maintained over time.

In this chapter, we’ll explore the early stages of TDD in Angular. We’ll start by discussing the role of TDD in Angular development and how it can help improve the quality of your code. Then, we’ll set up the development environment, which involves installing the necessary tools and dependencies.

Next, we’ll create a new Angular project and explore the various files related to writing tests, including the spec files, which contain the actual tests, and the karma.conf.js file, which is used to configure the testing framework.

Throughout this chapter, I will provide examples and best practices for writing effective tests in Angular, such as using descriptive test names, testing all code paths, and using dummy data to simulate different scenarios.

By the end of this chapter, you’ll have a solid understanding of the basics of TDD in Angular and how to start using it. Whether you’re new to TDD or looking to improve your skills, this chapter will provide you with the knowledge and tools you’ll need to create high-quality Angular applications using this approach.

We will cover the following topics:

Understanding TDD and its role in AngularSetting up the development environmentCreating a new Angular projectExploring different files related to writing tests

Technical requirements

To follow along with the examples and exercises in this chapter, you will need to have a basic understanding of Angular and TypeScript, as well as a code editor, such as Visual Studio Code, installed on your computer

All the code files for this chapter can be found at https://github.com/PacktPublishing/Mastering-Angular-Test-Driven-Development/tree/main/Chapter%201.

Understanding TDD and its role in Angular

In this section, we will explore the fundamentals of TDD and its role in Angular development. We’ll start by discussing the benefits of using TDD in general, such as improved code quality, faster development cycles, and reduced debugging time. Then, we’ll look at how TDD fits into the overall Angular development process and how it can be used to create scalable and maintainable applications.

What is Angular and TDD?

Angular is a popular open source JavaScript framework that’s used for building complex web applications. It was developed by Google and is widely used by developers around the world. Angular provides a set of tools and features that make it easy to build dynamic, responsive, and scalable web applications.

Angular is a component-based framework that allows developers to build reusable UI components. These components can be combined to create complex user interfaces, making it easy to maintain and extend the application. Angular also provides built-in support for testing, making it easy to write and execute tests for Angular applications.

TDD is a dynamic methodology in software development that prioritizes incrementally creating tests before the code is implemented. The TDD process revolves around a structured sequence known as the red-green-refactor cycle, which consists of the following stages:

Writing a failing test: Initiate the cycle by crafting a test that intentionally fails. This test serves as a specification for the desired functionality.Prohibiting overly complex tests: Emphasize the creation of tests that are only as intricate as necessary. Avoiding unnecessary complexity ensures that tests remain focused on specific functionalities, enhancing clarity and maintainability.Minimizing code implementation: Write the minimum code required to pass the failing test. This minimalist approach ensures that code is dedicated to fulfilling the specified requirements.

The iterative nature of TDD unfolds as follows: writing a failing test, implementing the code to pass the test, and refactoring the code to enhance code design and maintainability. This iterative loop persists until the entire code base is complete.

TDD’s unique approach to writing tests before code execution serves a dual purpose. First, it guarantees code correctness by aligning with predefined test requirements. Second, it fosters the creation of clean, maintainable, and adaptable code. Developers are encouraged to adhere to best practices, resulting in code that is easily comprehensible, modifiable, and extensible throughout the software development life cycle.

Now that we know what Angular is and looked at the benefits of using the TDD approach, let’s understand the red-green-refactor cycle.

The red-green-refactor cycle

The red-green-refactor cycle is a fundamental concept in TDD. It serves as a robust and systematic methodology in software development that offers developers a structured framework for incremental progress. This approach is designed to break down the development process into discrete, manageable steps, guaranteeing code correctness and alignment with predefined test requirements. Now, let’s delve into the technical nuances of each phase – red, green, and refactor – within this iterative process:

Red – writing a failing test:

The first step in the red-green-refactor cycle is to write a failing test. The test should define the desired behavior of the code and should be written in a way that it fails initially. This is called the “red” step because the test is expected to fail.

Green – writing code to pass the test:

The second step is to write the code that will make the test pass. The code should be minimal, and it should only be written to make the test pass. This is called the “green” step because the test is expected to pass.

Refactor – improving code without changing functionality:

Once the test has passed, the developer can refactor the code to enhance its design, readability, and maintainability by eliminating duplication, simplifying the code, and improving its readability. The key is to make improvements without altering the functionality covered bythe test.

In the next section, we will take a look at the benefits of the red-green-refactor cycle.

Benefits of the red-green-refactor cycle

The red-green-refactor cycle has several benefits, including the following:

Enhanced code quality: The red-green-refactor cycle ensures that the code is correct, reliable, and meets the requirements predefined in the testsAccelerated development: The red-green-refactor cycle allows developers to catch errors early in the development process, which saves time and reduces the cost of fixing bugsBetter collaboration: The red-green-refactor cycle encourages collaboration between developers, testers, and other stakeholders, which improves communication and helps to ensure that everyone is on the same pageSimplified maintenance: The red-green-refactor cycle produces code that is easier to maintain and extend, which reduces the cost and effort of future development

By using the red-green-refactor cycle, developers can build reliable, maintainable, and scalable software applications.

Next, we’ll learn how TDD is an important asset when it’s in use.

The role of TDD in Angular development

TDD plays a critical role in Angular development. By writing tests first, developers can ensure that the code is correct and meets the requirements defined in the tests. This ensures that the application is reliable and reduces the risk of bugs and errors. TDD also encourages developers to write clean, maintainable code that is easy to modify and extend, making it easier to maintain and update the applicationover time.

Angular provides built-in support for testing, making it easy to write and execute tests for Angular applications. The Angular testing framework provides a set of tools and features that make it easy to write unit tests, integration tests, and end-to-end tests for Angular applications. These tests can be run automatically as part of the build process, ensuring that the application is always tested and reliable.

In the next section, we’ll set up the development environment, which involves preparing the tools and resources needed to develop the project.

Setting up the development environment

With a theoretical understanding of TDD and its role in Angular application development, the next step is to configure our development environment so that we can apply TDD principles in Angular. To do this, we need to install the required tools to create an Angular project. By following the right steps, we can create a development environment that promotes effective and efficient development using TDD principles in Angular.

Setting up a development environment for Angular can be a bit more complex than setting up a general development environment. However, with the right guidance, it can be a straightforward process. Here, we will go over the steps you need to take to set up your Angular development environment. So, let’s get started.

Installing Node.js on Windows or macOS

Follow these steps to install Node.js on Windows or macOS:

Go to the official Node.js website (https://nodejs.org/en/) and click on the Download button for the LTS version. This will download the latest version of Node.js for Windows or macOS:

Figure 1.1 – Node.js home page