Star East 2009 - one hour describing why and how to use TDD and ATDD on an Agile team

1. Agile Testing:
Solving the Agilist’s
Dilemma
Star East
6 May 2009
11 May 2009 © Rob Myers 2009 1

2. Rob Myers
Rob.Myers@agileInstitute.com
•
Teaching Agile courses since 2002
•
XP/Agile coach since 1999
•
Using TDD to build software since
•
1998
• Professional software development
since 1986
• Blog:
PowersOfTwo.agileInstitute.com
11 May 2009 © Rob Myers 2009 2

3. The Agilist’s Dilemma
11 May 2009 © Rob Myers 2009 3

4. Debt
• Quality Debt
• Defects
• Design Debt
• Software design
resists change
• Testing Debt
• Manual testing
11 May 2009 © Rob Myers 2009 4

5. DILBERT: © Scott Adams/Dist. by United Feature Syndicate, Inc.
11 May 2009 © Rob Myers 2009 5

6. Why Wait?
Code Test
Months
Code Test
Weeks
Code Test
Days
Code Test
11 May 2009 © Rob Myers 2009 6

7. Instead…
Code
Write Test Run Test
Test Run Test Run Test
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8. Combine Advantages
Manual
Writing
Manual
Test
Testing
Cases
First
Later
Record
& TDD
Playback
Automated
11 May 2009 © Rob Myers 2009 8

9. “Move Mount Fuji”
11 May 2009 © Rob Myers 2009 9

10. Two Great Flavors
ATDD TDD
Written by testers, • Written by developers.
•
generally.
For the team.
• • For developers.
Run frequently by
• • Run frequently by
testers and testers and
developers. developers.
New tests fail until the
• • All tests pass 100%
story is done. Old during integration.
tests should all pass.
“Peanut Butter Cup” by Laura Godi
11 May 2009 © Rob Myers 2009 10

11. Benefits of ATDD
• Communication:
• Clarifies the meaning of the story.
• Story scope/boundaries: “Is it a
defect?”
• Progress: “We’re done!”
• Concise detection of defects.
• Less time troubleshooting and re-
testing.
• Relieves the Agilist’s Dilemma.
11 May 2009 © Rob Myers 2009 11

12. Team Activities by Iteration
Past Present Future
ATDD/TDD
Analysis/Estimation
Exploratory Testing
11 May 2009 © Rob Myers 2009 12

13. If Only…
• …We could automate the tests
without making them brittle…
• …We could write tests without having
to see the working product…
• …We could do so without having to
write in a programming language…
11 May 2009 © Rob Myers 2009 13

14. Inconceivable!
“You keep using that
word. I do not think it
means what you think it
means…”
-- Inigo Montoya
The Princess Bride
(1987)
11 May 2009 © Rob Myers 2009 14

15. Fit:
Framework for Integrated Tests
Invented by Ward Cunningham
11 May 2009 © Rob Myers 2009 15

16. Interface-Centric Tools
Slow.
•
Difficult to set up.
•
Numerous failures from one defect.
•
Failures do not identify the defect.
•
11 May 2009 © Rob Myers 2009 16

17. Business-Value-Centric Tool
11 May 2009 © Rob Myers 2009 17

18. Fit is Unique
• We can test any “layer,” thus
expanding our creative reach.
• We usually avoid the UI layer.
• Fit is simple. It does very little, and
you can do so much with it.
11 May 2009 © Rob Myers 2009 18

19. The First Martian Hotel
11 May 2009 © Rob Myers 2009 19

20. The “Column” Fixture
• For functions and calculations.
• Can be used to “Arrange” the test.
11 May 2009 © Rob Myers 2009 20

21. Fit Output
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_s

22. What Fit does to Your Tests
Your Fit test (HTML, Excel) Fit report (HTML)
Fit
Fit Fixture
(Test Code)
System Under Test
11 May 2009 © Rob Myers 2009 22

23. The “Row” Fixture
For asserting state. (No input.)
•
For lists.
•
Shows missing rows as failures.
•
Shows extra rows as failures.
•
Declarative.
•
11 May 2009 © Rob Myers 2009 23

24. The “Action” Fixture
• For a sequence of events.
• For simple scripting.
• Imperative.
11 May 2009 © Rob Myers 2009 24

25. Error Conditions
11 May 2009 © Rob Myers 2009 25

26. Tests Can Have Many Tables
11 May 2009 © Rob Myers 2009 26

27. A Team Using Fit for ATDD
1. Testers and other teammates enter
tests into Fit pages.
2. Developers develop Fit fixtures for the
tables.
3. The team collaborates on the shape of
the tables and Fit fixtures until they
express what needs to be
accomplished.
4. They run the tests and watch them fail
cleanly (RED, not YELLOW).
5. Developers develop until tests pass.
11 May 2009 © Rob Myers 2009 27

28. Fit Tools, and More Fit Tools
http://fit.c2.com/wiki.cgi?FitTools
11 May 2009 © Rob Myers 2009 28

29. Sample Test Organization:
Regression Focus
All Tests
Really Slow Acceptance
Tests Tests
Prior Current
Iterations Iteration
Iteration 1 Iteration 2
11 May 2009 © Rob Myers 2009 29

30. setup.html Files
setup.htm
All Tests
setup.htm
Really Slow Acceptance
Tests Tests
Prior Current
Iterations Iteration
setup.htm
Iteration 1 Iteration 2
aTest.htm
11 May 2009 © Rob Myers 2009 30

31. FITLIBRARY
And Other Improvements
11 May 2009 © Rob Myers 2009 31

32. The “Set Up” Fixture
11 May 2009 © Rob Myers 2009 32

33. The “Do” Fixture
11 May 2009 © Rob Myers 2009 33

34. Same Test, Additional Activities
11 May 2009 © Rob Myers 2009 34

35. Improving Upon RowFixture
• ArrayFixture: For ordered lists
(without having to create a position()
column).
• SubsetFixture: Ignores surplus
items.
11 May 2009 © Rob Myers 2009 35

36. Does TDD Work?
“The results of the case studies indicate
that the pre-release defect density of the
four products decreased between 40% and
90% relative to similar projects that did
not use the TDD practice. Subjectively, the
teams experienced a 15–35% increase in
initial development time after adopting
TDD.”
http://research.microsoft.com/en-us/projects/esm/nagappan_tdd.pdf,
Nagappan et al, © Springer Science + Business Media, LLC 2008
11 May 2009 © Rob Myers 2009 36

37. 11 May 2009 © Rob Myers 2009 37

38. BIBLIOGRAPHY
11 May 2009 © Rob Myers 2009 38

39. Fit for Developing Software
– Rick Mugridge
Prentice Hall
July 9, 2005
ISBN-10:
0321269349
ISBN-13:
978-0321269348
11 May 2009 © Rob Myers 2009 39

40. The Art of Agile Development
– James Shore & Shane Warden
O'Reilly Media, Inc.
October 26, 2007
ISBN-10:
0596527675
ISBN-13:
978-0596527679
11 May 2009 © Rob Myers 2009 40