INTRODUCTION TO BDD (Behaviour-Driven Development) Luis García Castro 

TESTING 2 Why is testing so important ? We can’t avoid to have bugs in our applications, but we must limit its presence and impact (and not only in release date) Inception Design Development Acceptance Maintenance 

3 Benefits of Unit Testing Tests create a feedback loop that informs the developer whether the product is working or not. ● Unit tests are fast ● Unit tests are reliable ● Unit tests isolate failures But tests made at the end of the project are only useful to exceed the mandatory coverage, they don’t provide many other benefits 

4 What is TDD ? TDD is a not just “adding tests first”, it’s a workflow 

5 Benefits of TDD TDD is the best way to discover how complex your code is becoming ● Do you need to mock 7 objects for a unit test? ● Do you have a setup method of >15 lines? ● Are you able to test all your code? By writing test first: ● You are becoming a consumer of your own API ● You are forced to think what responsibilities the given object should have ● You are creating a safety net for everyone 

Acceptance tests Customer tests … BDD Unit tests TDD Sonar Lint ... 6 Is it enough with unit tests ? Code Right vs Right Code 

7 What is BDD ? Behaviour-Driven Development “It’s about focusing on the behaviour of an application from the point of view of its stakeholders” Dan North 

8 Who is a stakeholder ? A stakeholder is anyone who cares about: ● What the application does ● How much it costs ● Whether it is secure ● Whether the network will hold ● Whether it complies with the law ● How easy it is to deploy and diagnose ● How well it is written and architected ● How easy it is to change 

9 A more formal definition of BDD BDD is a second-generation, outside-in, pull-based, multiple- stakeholder, multiple-scale, high-automation, agile methodology It describes a cycle of interactions with well-defined outputs, resulting in the delivery of working, tested software that matters Dan North 

10 BDD asks for an Outside-In approach Express a requirement as a Story ● As… I want… So that I… Define acceptance criteria as scenarios made up of steps ● Given… When… Then... Automate the scenarios ● So each step becomes running code 

11 BDD is about Comunication Business Team Requirements Examples to discuss Design and create code specification Examples to implement 

12 Simple requirements and examples Feature: Tracking deliveries As a Customer I want to see a status of my delivery So I can know when it’s going to be delivered Scenario: Clicking a tracking URL Given I am waiting for a delivery And I received a confirmation message When I click the tracking URL from the message Then I should see a status of my delivery 

13 Gherkin Gherkin is plain-text English (or any other of the 60+ supported languages) with a little extra structure. Is designed to be easy to learn by non-programmers, yet structured enough to allow concise description of examples to illustrate business rules in most real-world domains. In Gherkin each not-blank line should start with a keyword: Feature, Scenario, Given, When, Then, And, Background, ... 

14 Gherkin examples 

15 Main benefits of BDD ● Examples become unit tests and documentation ● Scenarios become acceptance tests and documentation ● Acceptance tests also become regression tests 

16 Benefits of BDD for developers ● BDD will help you focus ● BDD will give you confidence to refactor ● BDD will help you better undersand the customers needs 

17 Benefits of BDD for Product Owners ● BDD will give you a greater insight into the complexity of what you’re asking for ● BDD will give you transparency about what the team is doing in each iteration ● BDD will help your teams ship faster 

18 Benefits of BDD for Testers ● BDD will mean you can find bugs even before they have been written ● BDD will give you the best automatic regression tests ● BDD will free you to do interesting, creative, exploratory testing 

19 BDD + TDD Cycle 

20 Testing Pyramid 

21 Use BDD in almost any language ● Java ● Concordion ● Easyb ● JDave ● JBehave ● Javascript ● Protractor ● Jasmine ● Cucumber ● Python ● Behave ● Groovy ● Cucumber ● PHP ● Kahlan ● Behat ● .NET ● Concordion 

22 Questions ?