This document discusses Behavior Driven Development (BDD) for web applications. BDD aims to minimize gaps between requirements specification, design, implementation, and validation by focusing on conversations between business users and developers using a shared vocabulary. It builds on user stories and acceptance criteria to define what needs to be delivered. BDD tools like Cucumber can automate acceptance tests defined in plain language to support test-driven development. The document provides an example of using BDD to specify and test the addition of commenting functionality to a news website.

1. BDD for
Web Applications
Thomas Lundström, Softhouse
@thomaslundstrom
TelecomCity DevCon, Karlskrona
September 23, 2010

2. Agenda
• What is BDD?
• BDD for web
applications
• BDD + Traditional
QA?
http://www.flickr.com/photos/puntodevista/84796578/

3. BDD
• What is BDD?

4. * “BDD aims to bridge the gap bet ween
the differing views of computer
BDD
systems held by Business users and
Technologists. It is deeply rooted in the
success of TDD and is influenced by
ideas like Domain Driven Design. Its
focus is on minimizing the hurdles
bet ween specification, design,
implementation and confirmation of
the behaviour of a system.”
Stakeholders
http://www.flickr.com/photos/zunami/3709268689/

5. * Golden triangle bet ween analyst’s
requirements, acceptance tests from
BDD
the test department and the “Done”
criteria for a feature used by the
developers
* Team effort
- Analyst
- Tester
Reqs
- Developer/Architect
Test Done
http://www.flickr.com/photos/qthomasbower/3426242870/

6. User stories - example
BDD builds upon the
conversation taking place
in user stories and
acceptance criteria.
Context: comments for e.g.
articles on a news site
As a public user
I want to be able to view messages
So that I can see what my friends think

7. Acc. criteria - example Acceptance criteria
defines if the soft ware is
done
One story - Many
acceptance criteria
This is only 2 of the
Given that there are 3 messages in the comment page
possible acceptance
criteria for the story
When I view the comment page
Then I should see 3 messages
Given that the comment page is empty
When I view the comment page
Then I should see 0 messages

8. (If we work with iterations - the same
thing applies if we work pull-based)
BDD Before we do something, we need to agree
upon what we should deliver = before
stories are accepted into the iteration, we
define the acceptance criteria for the
story
Based on the acceptance criteria and our
estimations, we include X number of
stories to deliver in the iteration
Important: we can’t commit to deliver
something unless we know what to deliver
= be thorough in splitting a story in
acceptance criteria
How to use BDD in
an iteration?

9. * Focus on vocabulary
- user stories
BDD
- acceptance criteria
Ubiquitous language!
Vocabulary
http://www.flickr.com/photos/altemark/337248947/

10. BDD
* Outside-in
- onion
- use the words of the user, not the
programmer
* Connection DDD - BDD: use ubiquitous
language when specifying the user
words
* Unit-level tests are still needed
Outside-in
http://www.flickr.com/photos/redcherryhill/389325062/

11. This is a tool in your toolbox. Use as
needed.
BDD
No silver bullet
http://www.flickr.com/photos/williamhook/1506578592/

12. As said previously: The Holy Grail :)
Why BDD?
This is what I find the most interesting
with the whole discussion about BDD.
- executable specifications
- focus on requirements
- everything builds upon user stories/
acceptance criteria
http://www.flickr.com/photos/22280677@N07/3342653727/

13. Tools Ruby: Cucumber, RSpec
Java: JBehave,
cuke4duke
.NET: NBehave,
cuke4nuke
@deurell, http://twitpic.com/iqp9c

14. Focus on process - not tech!
Tools
Process
http://www.flickr.com/photos/nostri-imago/3137422976/

15. Tool architecture
Yellow = the part of the
BDD stack that you write
Language
Runner
Glue layer
SUT

16. BDD + Web apps Perfect marriage!
All web apps use the same
tech to communicate
HTML (+ javascript) is the
lingua franca for web
development
http://www.flickr.com/photos/rubyran2626/296913361/

17. cuke4duke + selenium
WebDriver = one of e.g.
HtmlUnit, Firefox,
Chrome, IE etc.
Gherkin Hooks = cuke4duke
methods + the page
object pattern
cuke4duke
Hooks
Selenium + WebDriver
HTML + js

18. Demo
• Domain: Comment functionality
• Adding
• Viewing
• (In the future, it’s possible to add
moderation, tagging etc)

19. Current functionality
Demo: current
functionality
• Viewing comments

20. New iteration Demo: add comments
* new feature
* new steps
* implement steps
* implement web app
• New feature: adding comments

21. New iteration
• New feature: paging

22. How to include this into
CI environment
the regular CI env?
Depends on what you
run
Here: easy with maven2
In .NET land, e.g. msbuild
or Ant/Java, let the
build script launching
the acceptance criteria
run
Results from the acc
criteria run should be
output to html so that
we know how far we’ve
gotten
• Run acceptance criteria in the build

23. Test automation
Is there a difference bet ween BDD and the test
automation we’ve previously used?
- It depends on how the test automation was done
- with BDD, we’ve got test automation aligned with
(that are) the requirements!
Earlier: test automation prone to breakage.
Why?
- dev changes stuff (button names etc) that test
automation uses (fixed by running everything in
the build; everyone is in charge of the build, instead
of only the test dept)
• BDD vs. Test automation? - Requirements churn (we can’t guard from that)
- Unstable tools (no guard here either)

24. Test automation -
imperative/declarative
http://www.benmabey.com/2008/05/19/imperative-vs-declarative-scenarios-in-user-stories/

25. Test automation -
imperative/declarative
BREAK
http://www.benmabey.com/2008/05/19/imperative-vs-declarative-scenarios-in-user-stories/

26. Test in a BDD process Shift in viewpoint:
previously, we
We use testers to transform
high-level stories to “do this,
do that” specs, which
preferably are automated.
It’s their speciality to find
these thngs!
• “You can not inspect quality into the
product; it’s already there”
- W. Edwards Deming

27. Test in a BDD process
Testers can go from performing
manual script labour to do more
useful stuff
- exploratory testing
- helping devs & analysts analyse the
problem
- Performance testing
The competence of the testers i.e.
translation of abstract Reqs ->
hands-on runnables is used when
defining acceptance criteria
http://en.wikipedia.org/wiki/File:Systems_Engineering_Process_II.gif

28. Thanks!
• Thomas Lundström, Softhouse
• thomas.lundstrom@softhouse.se
• Twitter: @thomaslundstrom
• http://blog.thomaslundstrom.com