The presentation made at Agile Testing Days 2009 by Thomas Lundström

1. BDD approaches for
web development
Thomas Lundström, Softhouse
Agile testing days
Oct 13, 2009

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

7. 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/

8. Why?
BDD
* Programmer-driven
* Non-user jargon
No silver bullet
http://www.flickr.com/photos/williamhook/1506578592/

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

10. User stories
As a <role>
I want to <perform something>
So that <benefit>

11. User stories - example
Context: A guestbook
As a public user
I want to be able to view messages
So that I can see what my friends think

12. Acceptance criteria Acceptance criteria
defines if the soft ware
is done
One story - Many
acceptance criteria
Given <pre-requisite state>
When <action>
Then <outcome>

13. Acc. criteria - example This is only 2 of the
possible acceptance
criteria for the story
Given that there are 3 messages in the guestbook
When I view the home page
Then I should see 3 messages
Given that there are 3 messages in the guestbook
When I view the home page
Then I should see 3 messages

14. (If we work with iterations)
BDD
Before we do something, we need to agree
upon what we should deliver = before
stories are pulled 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?

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

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

17. Tool architecture
Language
Runner
Glue layer
SUT

18. Tool architecture
Language
Runner
Web-runner
HTML

19. BDD + Web apps 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/

20. Cucumber + webrat
Gherkin
Cucumber
Cucumber+Webrat
HTML

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

22. Current functionality
Demo: current
functionality
• Viewing comments

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

24. New iteration
• New feature: paging

25. New iteration
• New feature: deleting comments

26. 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

27. 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)

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

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

30. Test in a BDD process
We use testers to
transform high-level
stories to “do this, do
that” specs. It’s their
speciality to find these
thngs!
• “Quality is not enforced by checking
afterwards, but designed into the
product” (my interpretation)
- James Bach, at a discussion during Øredev
2008

31. 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

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