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

Tidying up Test Suites

Have you ever felt frustrated when working with your test suites? They can easily become messy and overgrown, unless you’re actively tending to them. In this chapter, we’ll look at some of the ways you can keep your test suites tidy.

The techniques you’ll use to tidy test suites differ from the techniques you’d use in your application code. Application code requires building abstractions and encapsulating details, with deep layers of connecting objects. However, tests benefit from being shallow, with each test statement having a clear effect.

Another way to think of it is that normal program flow can take many different paths through the code, but test suites have just one flow – they are scripts that run from top to bottom. There is an absence of control logic, such as conditional expressions and loop constructs.

The primary mechanism you have to control complexity in test suites is abstracting functions that hide...