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

Refactoring the tests

In this section, we’ll look at some of the refactoring work we can do before we start thinking about the next feature. We’ll start by fixing the test warnings from the last section, then we’ll add a third test as a completeness test, and we’ll finish by adding some styles.

Refactoring and changing behavior

The usual definition of refactoring is any internal change that does not affect external behavior. It is a bit of a stretch to include CSS style changes in this, or indeed changes that remove warnings. But I find that early on in a project, there are always little changes such as these ones that need to be made. The key point is that your test suite is green and remains green throughout.

Cleaning up warnings

It’s important to clean up any warnings as they appear. That’s because without doing this, the test runner output becomes full of noise. We want the output to be as short as possible so that it’...