Introduction to TDD and BDD

Introduction to TDD and BDD

Presented to my colleagues at ING Direct Spain

Transcript

1. INTRODUCTION TO BDD (Behaviour-Driven Development) Luis García Castro
2. 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. 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. 4 What is TDD ? TDD is a not just “adding tests first”, it’s a workflow
5. 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
6. Acceptance tests Customer tests … BDD Unit tests TDD Sonar Lint ... 6 Is it enough with unit tests ? Code Right vs Right Code
7. 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. 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. 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. 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. 11 BDD is about Comunication Business Team Requirements Examples to discuss Design and create code specification Examples to implement
12. 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. 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. 14 Gherkin examples
15. 15 Main benefits of BDD • Examples become unit tests and documentation • Scenarios become acceptance tests and documentation • Acceptance tests also become regression tests
16. 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. 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. 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. 19 BDD + TDD Cycle
20. 20 Testing Pyramid
21. 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. 22 Questions ?