1. WhatIsTDD?

2. WhatIsTDD?
A Way to Design Software Incrementally
(while you code)

3. TwoWaysToDesign
Design before dev.
● Assumes requirements
are stable
● Implies design is the job
of a designer
● Can take a long time
● Makes designer think
ahead
Design during dev.
● Assumes requirements
will change a lot
● Design is the job of the
programmers
● Is real time
● Focuses on current
needs

4. Upfrontvs.IncrementalDesign
Upfront designers:
Define abstractions
Incremental designers:
Start from examples
and extract
abstractions based on
patterns

5. TestDrivenDevelopment
● Write one test that
describes a new
behavior
● Add the minimum of
code to make it pass
● Improve design by
refactoring code and
tests

6. KeepitSimple
Minimum code to make
the current test pass

7. KeepitClean
Refactor after each
small change

8. BeinFlow
● What's the next
behavior?
● What's the minimum
change to implement
it?
● What's the right
design?

9. TwoMainDifficulties
● Think at the problem, not the solution
– Problem: I want to play TicTacToe
– Solution: We need four classes and a main method
● Proof-based design
– Proof-based: I see duplication, remove it by
creating a class
– Assumption based: I will need a Game class

10. StartWithTDD

11. HowtoStart?
● What is the first test?
● What is the next
test?
● Am I going in the
right direction?

12. Remember
Incremental Design starts from examples,
extracts abstractions based on proof

13. BehaviorSlicing
●
Identify Input and Output
●
Specify behaviors: input –
action – output
●
Simplify: Identify first
increment of the problem
●
Order behaviors so that only
one thing changes

14. Contact me
http://www.mozaicworks.com
adrian.bolboaca@mozaicworks.com
@adibolb
Extend your mentoring & training
capacity
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www.mozaicworks.com

15. PhotoAttribution
http://home.dei.polimi.it/pinto/tdd/images/tdd.
gif
http://www.flickr.com/photos/hey__paul/75118
23952/sizes/m/in/photostream/
http://www.flickr.com/photos/ru_boff/8307297
704/sizes/m/in/photostream/

16. PhotoAttributions
http://www.flickr.com/photos/porsche-
linn/5738170905/sizes/l/in/photostream/
http://www.flickr.com/photos/argenberg/45090
9401/sizes/z/in/photostream/