Svelte with test-driven development : advance your skills and write effective automated tests with Vitest, Playwright, and Cucumber.js / Daniel Irvine.

Format:

Book

Author/Creator:

Irvine, Daniel, author.

Language:

English

Subjects (All):

Computer software--Testing.

Computer software.

Automatic test equipment.

Application software--Testing.

Application software.

Application software--Testing--Automation.

Physical Description:

1 online resource (250 pages)

Edition:

1st ed.

Place of Publication:

Birmingham, England : Packt Publishing Ltd., [2023]

Summary:

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 Purchase of the print or Kindle book includes a free PDF eBook 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.

Contents:

Cover

Title Page

Copyright and Credits

Contributors

Table of Contents

Preface

Part 1: Learning the TDD Cycle

Chapter 1: Setting up for Testing

Technical requirements

Creating a new SvelteKit project

Installing and running Playwright

Running Vitest

Preparing your development environment for frequent unit testing

Choosing your editor

Creating a shell alias

Changing the test runner to report each test name

Watching the test fail

Configuring support for Svelte component tests

Installing jsdom and testing library helpers

Writing a test for the DOM

Writing a first Svelte component test

Ensuring the DOM is cleared after each test run

Restoring mocks automatically

Optional configuration

Configuring Prettier's print width

Reducing the tab width in the Terminal

Summary

Chapter 2: Introducing the Red-Green-Refactor Workflow

Understanding the Red-Green-Refactor workflow

Thinking ahead with some up-front design

The Birthdays application

Writing a failing test

Making it pass

Repeating the process

Refactoring the tests

Cleaning up warnings

Adding a third test to triangulate

Adding styles to the component

Chapter 3: Loading Data into a Route

Using Playwright to specify end-to-end behavior

Writing the test and watching it fail

Understanding the difference between Vitest tests and Playwright tests

Deciding an approach to make the end-to-end test pass

Test-driving the load function

Test-driving the page component

Chapter 4: Saving Form Data

Adding a Playwright test for data input

Test-driving a SvelteKit form

Adding the form component to the page component

Test-driving a SvelteKit form action.

Building a factory for the FormData objects

Building a Vitest test suite for the form action

Chapter 5: Validating Form Data

Adding a Playwright test for validating form errors

Displaying SvelteKit form errors

Passing the form data through the page component

Validating data in the form action

Clearing the data store between tests

Chapter 6: Editing Form Data

Planning the path ahead

Adding a Playwright test for editing form data

Evolving the repository to allow ID lookup

Updating the form action to handle edits

Replacing items in the repository

Protecting against unknown identifiers

Updating return values to include identifiers

Updating the list page with a new edit mode

Adding a toggle mode to the page

Part 2: Refactoring Tests and Application Code

Chapter 7: Tidying up Test Suites

Using page object models in Playwright tests

Extracting an action helper

Extracting a factory method for creating data objects

Chapter 8: Creating Matchers to Simplify Tests

Test-driving the pass or failure of an expectation

Understanding matcher structure

Testing a matcher

Writing the toBeUnprocessableEntity matcher

Providing extra information in failure messages

Implementing the negated matcher

Updating existing tests to use the matcher

Chapter 9: Extracting Logic Out of the Framework

Migrating tests with a test todo list

Porting tests from the form action

Duplicating form validation behavior in the repository

Extracting common methods

Chapter 10: Test-Driving API Endpoints

Creating a service test with Playwright.

Adding an API endpoint for retrieving data

Adding an API endpoint for saving data

Adding an API endpoint for updating data

Chapter 11: Replacing Behavior with a Side-By-Side Implementation

Updating the route loader to use the API

Updating the page form action to use the API

Using a server hook to seed sample data

Chapter 12: Using Component Mocks to Clarify Tests

Avoiding component mocks

Avoiding overtesting using TDD

Using hand-rolled component stubs

Rendering all props within a component stub

Checking the ordering of component instances

Dealing with complex props

Dispatching component events

Using a component mock library

Installing the library

Writing tests using the componentDouble function

Chapter 13: Adding Cucumber Tests

Creating the feature file

Setting up a Playwright world object

Implementing the step definitions

Part 3: Testing SvelteKit Features

Chapter 14: Testing Authentication

Testing authentication with Playwright

Creating an auth profile for dev and test modes

Writing tests for login

Updating existing tests to authenticate the user

Testing authentication with Vitest

Defining a session factory

Updating existing tests for page load functions

Updating existing tests for form actions

Chapter 15: Test-Driving Svelte Stores

Designing a store for birthdays

Writing tests for reading store values

Writing tests for updating store values

Chapter 16: Test-Driving Service Workers

Adding a Playwright test for offline access

Implementing the service worker

Index

Other Books You May Enjoy.

Notes:

Includes index.

Description based on print version record.

ISBN:

9781837630950

183763095X

OCLC:

1388633679