Book Image

RSpec Essentials

By : Mani Tadayon
Book Image

RSpec Essentials

By: Mani Tadayon

Overview of this book

This book will teach you how to use RSpec to write high-value tests for real-world code. We start with the key concepts of the unit and testability, followed by hands-on exploration of key features. From the beginning, we learn how to integrate tests into the overall development process to help create high-quality code, avoiding the dangers of testing for its own sake. We build up sample applications and their corresponding tests step by step, from simple beginnings to more sophisticated versions that include databases and external web services. We devote three chapters to web applications with rich JavaScript user interfaces, building one from the ground up using behavior-driven development (BDD) and test-driven development (TDD). The code examples are detailed enough to be realistic while simple enough to be easily understood. Testing concepts, development methodologies, and engineering tradeoffs are discussed in detail as they arise. This approach is designed to foster the reader’s ability to make well-informed decisions on their own.
Table of Contents (17 chapters)
RSpec Essentials
About the Author
About the Reviewers

Using let and context

This scenario is very common, and inevitably will make the test harder to read, increasing the potential for misunderstanding the intent, which in turn will increase the likelihood of mistakes being made when the test or related code is changed. Before we see how to improve the test, we will learn about the let helper:

describe AddressValidator do
  let(:address) { {street: "123 Any Street", city: "Anytown"} }

  it "valid? returns false for incomplete address" do
    expect(AddressValidator.valid?(address)).to eq(false)

  it "missing_parts returns an array of missing required parts" do
    ).to eq([:region, :postal_code, :country])

  context "invalid characters in value" do

    let(:address){ {street: "123 Any Street", city: "Any$town%"} }
    it "invalid_parts returns keys with invalid values" do
       ).to eq([:city])