Test Driven Development (TDD) and Behaviour Driven Development (BDD) are very similar. I'll explain why the most important part of both acronyms is the first 'D' for Driven and why it would be better if the second 'D' stood for Design. We'll explore what challenges you might face when trying to adopt this way of working and what benefits you will reap when you succeed. And I'll explore why these approaches are even more important in the contexts of distributed teams and continuous delivery.

1. @sebrose h)p://cucumber.io
Seb Rose
Introduc)on to
TDD and BDD

2. @sebrose h)p://cucumber.io
• Contradic)on
• TDD
• BDD

3. @sebrose h)p://cucumber.io
BDD
- Behaviour Driven Development
ATDD
- Acceptance Test Driven Development
SbE
- Specifica@on by Example
TDD
- Test Driven Development

4. h)p://lizkeogh.com/2011/06/27/atdd-vs-bdd-and-a-po)ed-history-of-some-related-stuff/
What’s the
difference
between TDD,
ATDD, BDD
and SbE?
They’re
called
different
things

5. @sebrose h)p://cucumber.io
A group of people
specifying how some
soSware should behave
before implemen@ng it

6. @sebrose h)p://cucumber.io
• Work from the outside
• Use examples
• Ubiquitous language

7. @sebrose h)p://cucumber.io
• Contradic@on
• TDD
• BDD

8. @sebrose h)p://cucumber.io
h)p://www.growing-object-oriented-soSware.com/figures.html
From Growing Object-Oriented SoSware by Nat Pryce and Steve Freeman

9. @sebrose h)p://cucumber.io
• Write a failing test
• Make it pass (quickly)
• Refactor (un@l happy)

10. @sebrose h)p://cucumber.io
Improve the structure of
some code without
affec@ng its externally
observable behaviour.
Refactor

11. @sebrose h)p://cucumber.io
• Contradic@on
• TDD
• BDD

12. @sebrose h)p://cucumber.io
“BDD prac@@oners explore,
discover, define, then drive
out the desired behaviour of
soSware using conversa)on,
concrete examples, and
automated tests.”
h)ps://pragprog.com/book/srjcuc/the-cucumber-for-java-book
From Cucumber for Java Book by Seb Rose, Ma) Wynne and Aslak Hellesøy

13. @sebrose h)p://cucumber.io
h)p://www.growing-object-oriented-soSware.com/figures.html
From Growing Object-Oriented SoSware by Nat Pryce and Steve Freeman

14. Acceptance
criteria
User Story
Examples
Feature: Team Scoring
Teams start with zero score.
Correct answer gets points depending on
how difficult it is.
Scenario: Score starts at 0
Given I register a team
Then my score is 0
Scenario: Correct easy answer scores 10
Given I register a team
When I submit a correct easy answer
Then my score is 10
Scenario: Correct hard answer scores 50
Given I register a team
When I submit a correct hard answer
Then my score is 50

15. • Contradic@on
• TDD
• BDD
• ???

16. @sebrose h)p://cucumber.io
First ‘D’ is for Driven
• First specify the behaviour
• Then use the ‘failing’
specifica@on to drive
development

17. @sebrose h)p://cucumber.io
Second ‘D’ for Design?
• Listen to your tests
• Testability gets ‘baked in’
• Refactor un@l it feels right

18. @sebrose h)p://cucumber.io
• They’re all the same (mostly)
• Outside-in
• Examples
• Ubiquitous language
• Automated verifica@on

19. Seb Rose
Twi)er: @sebrose
Blog: h)p://cucumber.io
E-mail: seb@cucumber.io