Book Image

Hands-On Dependency Injection in Go

By : Corey Scott
Book Image

Hands-On Dependency Injection in Go

By: Corey Scott

Overview of this book

Hands-On Dependency Injection in Go takes you on a journey, teaching you about refactoring existing code to adopt dependency injection (DI) using various methods available in Go. Of the six methods introduced in this book, some are conventional, such as constructor or method injection, and some unconventional, such as just-in-time or config injection. Each method is explained in detail, focusing on their strengths and weaknesses, and is followed with a step-by-step example of how to apply it. With plenty of examples, you will learn how to leverage DI to transform code into something simple and flexible. You will also discover how to generate and leverage the dependency graph to spot and eliminate issues. Throughout the book, you will learn to leverage DI in combination with test stubs and mocks to test otherwise tricky or impossible scenarios. Hands-On Dependency Injection in Go takes a pragmatic approach and focuses heavily on the code, user experience, and how to achieve long-term benefits through incremental changes. By the end of this book, you will have produced clean code that’s easy to test.
Table of Contents (15 chapters)

Test-induced damage

In a 2014 blog post, David Heinemeier Hansson expressed that changes to a system for the sole purpose of making tests easier or faster resulted in test-induced damage. While I agree with David's intent, I am not sure we agree on the details. He coined this term in response to what he felt was excessive application DI and test-driven development (TDD).

Personally, I take a pragmatic approach to both. They are tools. Please try them out. If they work for you, fantastic. If not, that's fine too. I have never been able to get TDD to be as productive for me as other methods. Generally, I will write my function, at least the happy path, and then apply my tests. Then I refactor and clean.

Warning signs of test-induced damage