Book Review: BDD in Action by John Ferguson Smart (Manning)

As the subtitle of the book ‘Behavior-driven development for the whole software lifecycle’ suggests, this is a book describing Behaviour Driven Development for the different phases of software development.

It starts with a very general description of BDD, the problems that it addresses, the general principles and the origins of it, as well as the pros and cons in different organisations and team scenarios. Throughout this general description there are plenty of references and links for anyone wishing to have more details.

This is followed by a real life project, that goes through the phases of requirement analysis, creation of the features, stories and examples and the distinction and differences between each of them. There are various techniques described, including Feature Injection for identifying business goals and supporting features, Impact Mapping for high-level requirement visualisation, Purpose-Based Alignment Model for judging how much effort you should put into different features, and the identification of stakeholders and their roles. There is also a description about Real Options and Deliberate Discovery principles.

There are more detailed examples to automating scenario steps, described in different languages (Java, Python, .NET, Javascript) and diffent tools (JBehave, Cucumber-JVM, Behave, SpecFlow and Cucumber-JS). These are used to go from executable specifications to automated acceptance tests. There two separate chapters following that, describing the two different ways for automating the acceptance criteria depending on whether they are for the UI layer or the non-UI requirements.

Last but not least, there is a chapter dedicated to explaining the relationship between BDD, TDD and Unit Testing, another one describing the idea of living documentation, as well as reporting and project management, and finally the role of BDD in continuous integration (CI) and continuous delivery.

Throughout the text there are a lot of diagrams to help explain the ideas better, as well as a lot of references for more detail. Even though most of the examples are based in Java, the principles, ideas and techniques are easily applied to other languages and tools.

So, in summary this is a very useful book for anyone wanting to learn how Behaviour Driven Development can be used in practise. There are different sections that are targeted to different roles from business stakeholders, to testers and to developers. Hopefully when your whole team reads this book, the whole idea of BDD can be understood better, and used to build the software right as well as build the right software.

Disclaimer: This book was reviewd under the Manning reviewers program.

The user limit on the total number of inotify watches was reached or the kernel failed to allocate a needed resource. (Errno::ENOSPC)

Problem

When using the guard gem together with spork and cucumber and rspec to automate testing in your rails app, you get the following error:

which also causes the guard to stop running.

Solution

Looking at the directory where the error takes place it appears there are a lot of temp files in the public/uploads/tmp directory that are not cleared up (using carrierwave for image uploading).
Maybe adding an initializer as suggested here would solve the clearing up of the files.
Otherwise by manually deleting the files and running guard again, it should work as expected.

Adding Webrat, Cucumber and RSpec to a new Rails 3 project

Problem

You would like to start using BDD in a new Ruby on Rails 3 application, and would like to install Webrat, Cucumber and RSpec to your project.

Solution

Follow the steps below (taken from the RSpec Book), for creating a new Rails 3 application and adding the necessary testing frameworks:

  1. Create your new ruby on rails application: rails new my_app
  2. Go to your new application directory: cd my_app
  3. Edit your Gemfile to include the following:
    group :development, :test do
    gem "rspec-rails", ">= 2.0.0"
    gem "cucumber-rails", ">= 0.3.2"
    gem "webrat", ">= 0.7.2"
    end
  4. Use bundler to install all the gems and dependencies: bundle install
  5. Install the rspec files: script/rails generate rspec:install
  6. Install the cucumber files: script/rails generate cucumber:install
  7. Run the following and you shouldn’t be seeing any errors:
    rake db:migrate
    rake db:test:prepare
    rake spec
    rake cucumber