An Introduction to BDD

When a customer asks for a new feature to an application or a whole new application, how do you know where to start? Do you start writing production code right away? How do you know the code you are writing is taking you down the correct path? How do you know the code you are writing fulfills your customer's business problem? How do you know the code you are writing will stay correct when your customer asks for another new feature or you fix a bug in another part of the application? Unit testing has been a concept around for quite a while. It ensures that the code you write is logically correct and stays correct. The problem is that the stake holders of this new feature can not read your code and ensure that it is correct before you write your production code. Another problem is that unit testing is something that you do after you write your code. It is an afterthought and does not prevent you from writing the wrong code conceptually. The third problem is that stake holders often frown upon this. They hear the word "testing" and they think that it is something that can be skipped or bolted on later. What if you wrote your tests first? What if your customers could read your code like specifications? If so, then these should not be called "tests", but rather specifications. This "test first development" is called BDD or "behavior driven development". It allows your customers to read your tests as specifications in English phrases. It allows the developers to travel down the correct path and not write code that is not needed or wrong. In this session, we will review what BDD is and why you should adopt this concept in your next project. We will discuss and implement a feature from concept to implementation from the real world. We will then write this feature out using Ruby, Rails, and a BDD framework called Cucumber.

Transcript

1. Behavior Driven Development How it can open your eyes 1
2. Brilliant Fantastic | | jamie@brilliantfantastic.com @jwright 2
4. Disclaimer It works on my machine 4
5. Jeez Not another *DD Process 5
6. How do you verify what you are building is the thing that the customer wants? 6
7. 56% of all bugs can be traced to errors made during the requirements stage -- Tom DeMarco 7
8. Minimizing The Feedback Loop 8
9. Get Requirements Analyze Design Code Test 9
10. Code Test Test Driven Development “Test Eventually” / “Test While” Design 10
11. It’s not about testing It’s about design 11
12. Inspection to find defects is a waste -- Shingeo Shingo 12
13. Inspection to prevent defects is essential -- Shingeo Shingo 13
14. Code Test Test Driven Development “Test First” Design 14
15. Red > Green > Refactor 15
16. Design is a process not a phase 16
17. Design Code Test Behavior Driven Development Analyze 17
18. Extends TDD 18
19. Common Language between developers & customers 19
20. Gives You a starting point 20
21. Gherkin The Common Language 21
22. Feature: In order to As a I want to Feature name / identifier Value proposition Role / Actor Feature description Feature: Add an item to my cart In order to purchase an item As an online shopper I want to place something in my cart to show intent that I plan on purchasing it 22
23. Scenario: Given When Then Acceptance criteria Setup (arrange) User action / change occurs (act) Outcome (assert) Scenario: A user without an account can add items to their cart Given I do not have an account And a product exists with name: “Ton-Ton Sleeping bag” When I browse to the product’s detail page And I click “Add to Cart” Then I should be on the cart page And I should have an item in my cart with name: “Ton-Ton Sleeping bag” 23
24. Outside-in Development 24
25. Write Scenarios 25
26. Steps are pending 26
27. Write steps definitions 27
28. Go down to RSpec 28
29. Write code example 29
30. Make example pass 30
31. Go back up to Cucumber 31
32. Make steps pass 32
33. Refactor! 33
34. Mindsets Not Toolsets 34
35. Tools are just tools....using them doesn’t automatically mean you’re doing BDD -- The RSpec Book 35
36. Tools for Ruby 36
37. RSpec https://github.com/dchelimsky/rspec 37
38. Cucumber https://github.com/cucumber/cucumber 38
39. Friends https://github.com/ianwhite/pickle https://github.com/jnicklas/capybara I got nothing... 39
40. Tools for .NET 40
41. SpecFlow http://www.specflow.org/ 41
42. Example use case 42
44. Backgrounds provided by http://simpledesktops.com 44
45. A Must Read The RSpec Book: BDD with RSpec, Cucumber, & Friends 45
46. Brilliant Fantastic | | jamie@brilliantfantastic.com @jwright 46