Book Image

Test-Driven Development in Go

By : Adelina Simion
Book Image

Test-Driven Development in Go

By: Adelina Simion

Overview of this book

Experienced developers understand the importance of designing a comprehensive testing strategy to ensure efficient shipping and maintaining services in production. This book shows you how to utilize test-driven development (TDD), a widely adopted industry practice, for testing your Go apps at different levels. You’ll also explore challenges faced in testing concurrent code, and learn how to leverage generics and write fuzz tests. The book begins by teaching you how to use TDD to tackle various problems, from simple mathematical functions to web apps. You’ll then learn how to structure and run your unit tests using Go’s standard testing library, and explore two popular testing frameworks, Testify and Ginkgo. You’ll also implement test suites using table-driven testing, a popular Go technique. As you advance, you’ll write and run behavior-driven development (BDD) tests using Ginkgo and Godog. Finally, you’ll explore the tricky aspects of implementing and testing TDD in production, such as refactoring your code and testing microservices architecture with contract testing implemented with Pact. All these techniques will be demonstrated using an example REST API, as well as smaller bespoke code examples. By the end of this book, you’ll have learned how to design and implement a comprehensive testing strategy for your Go applications and microservices architecture.
Table of Contents (18 chapters)
1
Part 1: The Big Picture
6
Part 2: Integration and End-to-End Testing with TDD
11
Part 3: Advanced Testing Techniques

Exploring mocks

In this section, we will explore one of the mechanisms that allows us to test code that relies on dependencies. We will see how to use and generate mocks, allowing us to verify the UUT in isolation from the behavior of its dependencies.

Mocks are sometimes known as test doubles and are a simple but powerful concept. They satisfy the interfaces but are fake versions of the real implementations. We have full control over these fake implementations, giving us the freedom to control their behavior. However, if the real implementation changes and our mocks do not, then our tests will give us false confidence.

In Go, we have the following different mocking options:

  • Function substitution: This means sending replacement fake functions to the UUT. This is easy to do in Go, which has native support for higher-order functions. We can override function variables and parameters, replacing the behavior of the UUT.
  • Interface substitution: This means injecting fake...