Interfaces, Functions and Modules in Go: Structuring Your Code for TDD Without Adding Unnecessary Complexity

Mon, 15 Dec 2025 10:08:49 +0200

I. Introduction

Go is a minimalist language, but this simplicity can sometimes make developers feel like something is “missing” — especially when dealing with more advanced architectures, Test-Driven Development, or the need to mock dependencies. Developers coming from Java, C#, or Python often ask the same questions:

Should I turn all my functions into structs + interfaces to test them?
How should I organize my packages to keep them modular and testable?
Where should interfaces live — in the provider or the consumer?
How do I isolate a package that only exports functions?
How does Go automatically detect signature changes?

II. Go’s Model: Simple, Modular, but Different

Unlike Java or C#, Go does not rely on inheritance, classes, or heavy dependency injection frameworks.

Modularity on Simple Enough Blog

Interfaces, Functions and Modules in Go: Structuring Your Code for TDD Without Adding Unnecessary Complexity

I. Introduction

II. Go’s Model: Simple, Modular, but Different