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
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Matchers


We've been using RSpec's eq matcher to make assertions so far. We don't absolutely need this or any of RSpec's other matchers. We could use standard Ruby or define our own helper methods, like so:

describe 'no matchers' do
  it "valid? returns false for incomplete address" do
    expected = AddressValidator.valid?(address)
    if expected != false
      # RSpec's fail method allows us to manually fail an example 
      fail "Expected #{expected} to have value of false"
    end
  end
end

There are a few problems with this approach. First, it is clumsy to write and read. Second, without a standard way of handling assertions, we're likely to wind up with a bunch of variations on the code above, making our output confusing. Finally, it is very easy to make mistakes with this kind of code, leading to invalid test results.

RSpec's matchers offer a simple and elegant syntax for making assertions. This makes it easy to write tests and also makes the intent of the test much clearer, allowing...