Book Image

Svelte with Test-Driven Development

By : Daniel Irvine
Book Image

Svelte with Test-Driven Development

By: Daniel Irvine

Overview of this book

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.
Table of Contents (22 chapters)
1
Part 1: Learning the TDD Cycle
8
Part 2: Refactoring Tests and Application Code
16
Part 3: Testing SvelteKit Features

Loading Data into a Route

SvelteKit is very much about routing: figuring out what to display once your browser requests a page at a specific location. For example, the /birthdays route that we’ll work on in this chapter. Part of that routing is ensuring that the route has the data available to it. In this chapter, you’ll see how you can test-drive SvelteKit’s load function for pulling that data into a component.

You’ll also see how Playwright can be used to build an end-to-end test that proves all the various components of this system.

This chapter covers the following:

  • Using Playwright to specify end-to-end behavior
  • Deciding an approach to make the end-to-end test pass
  • Test-driving the load function
  • Test-driving the page component

By the end of the chapter, you’ll have test-driven a functioning SvelteKit route that you can view in your web browser, and you’ll have learned the key differences between Playwright...