ABAP CodeRetreat Frankfurt 2016. TDD talk by Hendrik Neumann

1. TDD – Test Driven Development
Hendrik Neumann

2. Agenda
(1) Unit Testing
(2) ABAP Unit
(3) Test Driven Development

3. Unit Testing

4. Unit Testing
Definition

5. Unit Testing
Unit Testing is a method by which
individual units of source code are
tested to determine if they are fit to
use.

6. Unit Testing
Unit Testing is a method by which
individual units are e.g.ource code
fittMethods of t Function Modules fit
Function Groups
fiMoModule Pools Function
Functn Reports
Methods
Function Groups

7. Unit Testing
aim:
Find bugs early
Write once, run often
Effective Tests must be automated
solution:
xUnit Frameworks

8. xUnit Framework

9. xUnit Framework
Definition

10. xUnit Framework
Provides an automated solution with no
need to write the same tests many times
and no need to remember what should be
the result of each test.

11. xUnit Framework
How does it work?

12. xUnit Framework
setup()
creates object under test
– used in all tests

13. xUnit Framework
setup()  test_method()
Clear up your
mess..
calls object under test
– e.g. a public method
with test data

14. xUnit Framework
setup()  test_method()
assert_*()–methods
verify the return value of
the object under test using
xUnit’s assert methods

15. xUnit Framework
setup()  test_method() teardown()
Clear up your
mess..

16. xUnit Framework
setup()  test_method() teardown()
test_method()
test_method()
test_method()
test_method()
test_method()
test_method()

17. ABAP Unit

18. ABAP Unit
SAP‘s xUnit implemenation

19. ABAP Unit
cl_abap_unit_assert=>assert_equals(
msg = 'Test msg'
act = act
exp = out->( )
).

20. assert_*()-Methods

21. ABAP Unit in ADT

22. ABAP Unit
Local test classes for global
development artifacts
In Reports, Function Modules and
Classes
Not acitve on production systems

23. ABAP Unit
• Tools integration:
–ABAP Workbench
–Code Inspector Integration
–ABAP Unit Browser
–ABAP Test Cockpit (ATC)
–ABAP in Eclipse

24. Test Driven Development

25. Test Driven Development
• Never
• After you wrote your code
• Before you write your code
When do you write your Unit Tests?

26. Test Driven Development
• Never
• After you wrote your code
• Before you write your code
When do you write your Unit Tests?
Test Driven Development

27. Test Driven Development
Test 1st

28. Test Cycle
Test
Write a test that expresses how you’ll use
the code and what you need it to do.

29. Test Cycle
Write enough code to get
the test to pass, but no
more.
Code
Test

30. Test Cycle
Code
Test
Refactor
Clean up the code to
remove redundancy and
improve the design.

31. Test Cycle
Code
Test
Refactor

32. Test Cycle
Code
Test
Refactor

33. Test Cycle
Code
Test
Refactor

34. Test Cycle
Code
Test
Refactor

35. Green Bar Patterns

36. Green Bar Patterns
Fake it till you make it
• Start with hardcoded results and wait
until tests force them to become real

37. Green Bar Patterns
Triangulate To Abstraction
• Make the code abstract only when you
have two or more examples

38. Green Bar Patterns
Obvious Implementation
• aka Don‘t be stupid
• If you really know the right way to
implement it, do it that way

39. Have FUN!

40. Backup

41. Code Kata: Roman Numerals
Rules:
• smaller number in front of a larger number  subtraction
• all else  addition
• put only one smaller number in front of a larger number
• ones, tens, hundreds and thousands are separate items
I The numeral one. II is two, III is three.
V The numeral 5. IV is 4, VI is 6, VII is 7, VIII is 8.
X The numeral 10. IX is 9, XI is 11, etc.
L The numeral 50. XL would be 40.
C
The numeral 100. C is short for the Latin word Centum,
but Century is eaysier to remember ;-)
D The numeral 500.
M The numeral 1000.