An Architecture for Behaviour-Driven Development in Swift

This article will show you how we can do behaviour-driven development (BDD) in Swift — frictionless

Photo by Christopher Gower on Unsplash

Behavior-driven development (BDD) is a software development process that encourages collaboration among developers, quality assurance experts, and customer representatives in a software project.

It encourages teams to use conversation and concrete examples to formalize a shared understanding of how the application should behave. It emerged from test-driven development (TDD).

Behavior-driven development combines the general techniques and principles of TDD with ideas from domain-driven design and object-oriented analysis and design to provide software development and management teams with shared tools and a shared process to collaborate on software development. [Wikipedia]

BDD is a variant of TDD where the goal of testing is to increase confidence for stakeholders through evidence, as Dan North — who coined the phrase “Behaviour-Driven Development” — puts it.

I think that in this context it makes more sense to talk about “specifications” rather than “tests”.

In this article, I will show how my architecture “Khipu” plays along nicely with the BDD tools Quick and Nimble.

Quick is a dedicated BDD framework. Nimble is a matcher framework, enabling tests that read like English sentences.

Let’s assume we build a point of sale (POS) app for taking and managing orders in a restaurant.

We meet with our product owner, and he shares his specifications (short: specs) with us.

• the app will be centred around Tables
• Tables have a name and contain an Order
• a order can be empty or contain a number of Positions
• Positions contain an Article and a quantity

We prepare the specs in Quick using the following code:

import Quick
import Nimble

final class TableSpecifications:QuickSpec {
    override class func spec() {
        describe("Table") {
            context("creation") {
                it("has an identifier") {…