Svelte with Test-Driven Development: Advance your skills and write effective automated tests with Vitest, Playwright

Build robust and performant applications by developing SvelteKit applications using automated testing and TDD techniques, including unit and end-to-end testing, custom matchers, component mocking, and authentication

Key Features
Understand and master the test-driven development (TDD) workflow
Explore the principles of unit testing with Vitest and end-to-end testing using Playwright and Cucumber.js
Leverage practical examples of unit tests covering a range of SvelteKit framework features

Book Description
Svelte is a popular front-end framework used for its focus on performance and user-friendliness, and test-driven development (TDD) is a powerful approach that helps in creating automated tests before writing code. By combining them, you can create efficient, maintainable code for modern applications. Svelte with Test-Driven Development will help you learn effective automated testing practices to build and maintain Svelte applications.

In the first part of the book, you'll find a guided walkthrough on building a SvelteKit application using the TDD workflow. You'll uncover the main concepts for writing effective unit test cases and practical advice for developing solid, maintainable test suites that can speed up application development while remaining effective as the application evolves. In the next part of the book, you'll focus on refactoring and advanced test techniques, such as using component mocks and writing BDD-style tests with the Cucumber.js framework. In the final part of the book, you'll explore how to test complex application and framework features, including authentication, Svelte stores, and service workers.

By the end of this book, you'll be well-equipped to build test-driven Svelte applications by employing theoretical and practical knowledge.
What you will learn

Create clear and concise Vitest unit tests helping the implementation of Svelte components
Use Playwright and Cucumber.js to develop end-to-end tests that simulate user interactions and test the functionality of your application
Leverage component mocks to isolate and test individual components
Write unit tests for a range of Svelte framework features
Explore effective refactoring techniques to keep your Svelte application code and test suites clean
Build high-quality Svelte applications that are well-tested, performant, and resilient to changes

Who this book is for
This book is an essential guide for Svelte developers seeking to enhance their development process by learning the TDD workflow and its application. Whether you are an experienced developer or new to automated testing, this book helps you gain a practical approach to improving your workflow. The examples are written in JavaScript, making them accessible to all developers, including TypeScript developers.

Table of Contents
Setting up for Testing
Introducing the Red-Green-Refactor Workflow
Loading Data into a Route
Saving Form Data
Validating Form Data
Editing Form Data
Tidying up Test Suites
Creating Matchers to Simplify Tests
Extracting Logic Out of the Framework
Test-Driving API Endpoints
Replacing Behavior with a Side-By-Side Implementation
Using Component Mocks to Clarify Tests
Adding Cucumber Tests
Testing Authentication
Test-Driving Svelte Stores
Test-Driving Service Workers