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2. Testing as a career…? Easier to get in, get ahead
Blame others, not get blamed
Still can code

3. Testing as a career…? Easier to get in, get ahead
Blame others, not get blamed
Still can code

4. Test-savvy coders are good coders
Testing as a career…?
Test-savvy coders are good coders

5. SUT
Test case

6. SUT
Test case
Test case

7. SUT
Test case
Test case
To do this, we have to design these test cases

8. When do we define test cases? Are they pre-determined or on-the-fly?
SUT
Test case
Test case

9. SUT Pre-determined or on-the-fly?
Test case
Test case
How much internal info about the SUT should be revealed to the test case designer?

10. SUT How to choose which test cases to use and which to discard?
Pre-determined or on-the-fly?
SUT
Test case
Test case
How much info revealed?

11. CS2103/T, Lecture 8, Part 3, [Oct 7, 2016]
Pre-determined or on-the-fly?
How to choose?
Heuristics for Better Test Case Design
CS2103/T, Lecture 8, Part 3, [Oct 7, 2016]
How much info revealed?

12. SUT Pre-determined or on-the-fly? How to choose?
Test case
Test case
How much info revealed?

13. Pre-determined or on-the-fly?
SUT
Test case

14. Pre-determined or on-the-fly?
SUT
Test case

15. SUT scripted testing  which one? exploratory testing  which one?
Pre-determined or on-the-fly?
SUT
Test case
scripted testing  which one?
exploratory testing  which one?

16. SUT scripted testing  pre-determined exploratory testing  on-the-fly
Pre-determined or on-the-fly?
SUT
Test case
scripted testing  pre-determined
exploratory testing  on-the-fly
Most of the jokes done by comedians are scripted. They sometimes throw in a few on-the-spot jokes, but even they are not totally random.
how to choose?

17. Pre-determined or on-the-fly?
Scripted+Exploratory
SUT
Test case

18. Pre-determined or on-the-fly?
Scripted+Exploratory
SUT
Test case

19. Scripted+Exploratory
SUT
Test case

20. Scripted+Exploratory
SUT
Test case
Test case
How much info revealed?

21. Scripted+Exploratory
SUT
Test case
Test case
How much info revealed?

22. SUT
Developer
Tester
Test case
How much info revealed?

23. SUT
Developer
Tester
Test case
How much info revealed?

24. Glass-box / a.k.a white box
Gray-box
Test case
Black-box
How much info revealed?

25. Test case
How much info revealed?

26. Scripted+Exploratory
SUT
Test case
Test case
Black/Glass/Gray-box

27. Scripted+Exploratory
SUT
Test case
Test case
Black/Glass/Gray-box

28. Acceptance testing is most likely to be…
Black box testing
White box testing
Gray box testing

29. SUT How to choose? Scripted+Exploratory Black/Glass/Gray-box Test case

30. How to choose?
Why choose?
Some heuristics
Test case

31. No need to celebrate! This is a simulation 
[extra] BSoD
No need to celebrate! This is a simulation 
[CS2103]

32. Windows without bugs? That’s crazy talk!
[extra] BSoD
Windows without bugs? That’s crazy talk!
[CS2103]

33. How to choose?
Why choose?
Test case

34. How to choose?
Why choose?
Test case

35. How to choose?
Why choose?
[Effectiveness & Efficiency]

36. Both tested the same system
How to choose?
Why choose?
Dilbert
Wally
Both tested the same system
[Effectiveness & Efficiency]
Found 20 bugs
Found 10 bugs

37. Both tested the same system
How to choose?
Why choose?
Dilbert
Wally
Both tested the same system
[Effectiveness & Efficiency]
Found 20 bugs
Found 20 bugs
Used 100 test cases
Used 40 test cases

38. How to choose?
Why choose?
[Effectiveness & Efficiency]
A test case should have a reasonable chance of finding a new bug not found by the other test cases.

39. How to choose?
E&E of testing
Some heuristics
Test case

40. How to choose?
E&E of testing
Some heuristics
Test case

41. Equivalence partitioning
How to choose?
E&E of testing
Some heuristics
Test case
Equivalence partitioning

42. Equivalence partitioning
How to choose?
E&E of testing
Some heuristics
Test case
Equivalence partitioning

43. Equivalence partitioning

44. 77577 OR tinyurl.com/answerpost
Equivalence partitioning
isValidMonth (int m): boolean
Description:
checks if m is in the range [1..12]. returns true if m is in the range, false otherwise.
Which values would you use to test this isValidMonth method?
cases {value1 value2 …}
e.g. cases 1 4 9
OR tinyurl.com/answerpost

45. Pass/fail? Hmmm… interesting. Let me try 275 Should he? Why not?
Equivalence partitioning
isValidMonth (int m): boolean
Description:
checks if m is in the range [1..12]. returns true if m is in the range, false otherwise.
Pass/fail?
Hmmm… interesting.
Let me try 275
Test case 23:
Input: 273
Expected: false
Test Case 12
Test Case 13
Test case 23:
Input: 274
Expected: false
Should he?
Why not?
Actual: true
Actual: true

46. 275 Must be broken too! Broken! Broken! isValidMonth (int m): boolean
Equivalence partitioning
isValidMonth (int m): boolean
275
273
274
Must be broken too!
Broken!
Broken!

47. Equivalence partitioning
isValidMonth (int m): boolean
275
273
274

48. 275 isValidMonth (int m): boolean 273 274 Equivalence partitioning
MIN_INT 1 12 13
MAX_INT
275
273
274

49. isValidMonth (int m): boolean
Equivalence partitioning
isValidMonth (int m): boolean
MIN_INT 1 12 13
MAX_INT

50. Equivalence partitioning
How to partition?

51. Equivalence partitioning
Input space
Output space
SUT

52. SUT Equivalence partitioning Output space Input space
Input partition 1
Input partition 2
Input partition 3
Output 1
Output 2
Output 3
Input space
Output space
Input partition 1a
SUT
false
true

53. SUT Equivalence partitioning Input partition 1 Output 1
Input partition 1a
Input partition 1b
SUT
false
true

54. Equivalence partitioning

55. Why does i need more than one eq. partition?
Equivalence partitioning
Why does i need more than one eq. partition?
int square (int i)
Description: returns the the square value of i

56. Description: returns the the square value of i
Equivalence partitioning
int square (int i)
Description: returns the the square value of i
+√MAX
-√MAX -1
MIN
MAX

57. Description: returns the the square value of i
Equivalence partitioning
int square (int i)
Description: returns the the square value of i
+√MAX
-√MAX -1
MIN
MAX

58. It helps to improve E&E by …
How to choose?
E&E of testing
Some heuristics
Test case
Equivalence partitioning
An Eq. partition is a …
It helps to improve E&E by …

59. To be continued in the next lecture …