Lập trình hướng kiểm thử - Test Driven development

1. Test Driven
Development
LE ANH
APOLLO13.VN

2. Outline
 Overview about TDD
 How to do ?
 TDD by Example
 Why use TDD ?
 Common mistakes in TDD
 When we use TDD ?
 Q&A

3. Overview about TDD
TDD stand for Test Driven Development (Test Driven Design)

4. Overview about TDD
Regardless of the programming language

5. Overview about TDD
TDD is a strong methodology
Without TDD TDD

6. How to do TDD?
Do it in baby stepsIs TDD Difficult ?

7. How to do TDD?
Mantra of TDD is “Red/Green/Refactor”

8. How to do TDD?
Red text is 3C rule. They help raise your idea

9. How to do TDD?
 We have a user story, use 3C rule to make your idea (baby
requirement)
Allow user input a
string to set the
display name when
he login. Max length
of string is 125
characters

10. How to do TDD?
 String can contain special characters ?
 What kind of special characters (!@#$%^&...) ?
 String can contain space ?
 String can contain number ?
 Min length of string ?
 String can not contain select, delete, update
because of SQL injection
 String can be duplicate ?
Note : Don’t think the requirement is very simple therefore we don’t
need to confirm with PO. Confirmation is a way to prevent bugs

11. TDD by examples
 Example 1: write a method that reverse last 2
characters of string.
 If null  return null, if empty  return empty, if
length of string equal 1  return itself
 Ex: “A”  “A”, “” “”, null  null, “AB” “BA”,
“RAIN”  “RANI”

12. TDD by examples
 Create first test case

13. TDD by examples
 Can not compile because StringHelper class is not created

14. TDD by examples
 After StringHelper class is created, run ALL TEST CASE to see
they(or one of them) fail

15. TDD by examples
 Make a litte change to pass this test cases
Question : Who has a better implementation ?

16. TDD by examples
 Run ALL TEST CASES to see they pass

17. TDD by examples
 We have just finished a baby step of TDD cycle. Repeat it
again.

18. TDD by examples
 After StringHelper class is created, run ALL TEST CASE to see
they(or one of them) fail

19. TDD by examples
 Refactor code to pass this test case

20. TDD by examples
 Run all test cases to see they pass

21. TDD by examples
 Refactor test code if necessary

22. TDD by examples
 Add new test case

23. TDD by examples
 After StringHelper class is created, run ALL TEST CASE to see
they(or one of them) fail

24. TDD by examples
 Refractor code to pass the test case

25. TDD by examples
 Run all test cases to see they pass

26. TDD by examples
 Add new test case, this test case will be pass without any
changes

27. TDD by examples
 Add new test case, this test case will be fail

28. TDD by examples
 Refactor code

29. TDD by examples
 Run all test cases, if they pass and you don’t have any test
case. The TDD cycle is completed. Refactor code if necessary

30. Why use TDD ?
Clean code

31. Why use TDD ?
Without TDD Prevent bugs by TDD

32. Why use TDD ?
Design document

33. Why use TDD ?
Maintainable, flexible, easily extensible

34. Why use TDD ?
TDD change your mindset a bout programming & testing. You can
become a better programmer

35. TDD by examples
Example 2: Refer the below link
http://apollo13.vn/agile/mot-vi-du-tdd-voi-c.html

36. Common mistakes in TDD

37. Summary

38. Q&A
 What is the position of tester in TDD ?
 What is BDD/ATDD ?
 When we use TDD ?
 Is TDD dead ?
 Some questions from audiences…..