The document discusses test-driven development (TDD) and provides an overview of the TDD process and benefits. It describes how TDD encourages writing decoupled, well-designed code and helps find bugs through automated testing. While TDD may initially take longer, it improves code quality and maintainability. The document also covers challenges of testing database interactions and provides examples of different approaches like mocking databases, using DBUnit, or testing with Codeception.

1. Making Friends with
TDD
John Cleary
Lead Web Developer, DocNet
@TheRealBifter

2. So, What is TDD?

3. 10 Write one test
20 Run tests (they fail)
30 Write code to make test pass
40 Run tests again (they pass)
50 Refactor (code AND tests)
60 Run test (they still pass)
70 Goto 10

4. Red
GreenRefactor

5. Red
GreenRefactor
Write

6. a

7. failing

8. test

9. Red
GreenRefactor
Write

10. a

11. failing

12. test
Fix

13. the

14. test

15. Red
GreenRefactor
Write

16. a

17. failing

18. test
Fix

19. the

20. test
Make

21. it

22. pretty

23. Why do it?

24. 1. Improved Code Design

25. Classes that are easy to test are by definition decoupled.
1. Improved Code Design

26. Classes that are easy to test are by definition decoupled.
Encourages refactoring
1. Improved Code Design

27. 2. Verification

28. Fewer bugs
2. Verification

29. Fewer bugs
Easier to maintain
2. Verification

30. Awesome - let’s do it, right?

31. Awesome - let’s do it, right?
Wait!

32. Does it take longer?

33. Does it take longer?
Maybe, maybe not.

34. Is it harder?

35. Is it harder?
For sure!

36. But it wrecks my creativity,
dude?

37. But it wrecks my creativity,
dude?
Really? Do some prototypes man!

38. Could we get these benefits
without TDD?

39. Could we get these benefits
without TDD?
No, but yeah, but no...

40. Awesome, let's do it!
(for real this time)

41. Recently Used List Class

42. Recently Used List Class
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

43. Recently Used List Class
A recently-used-list is initially empty.
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

44. Recently Used List Class
A recently-used-list is initially empty.
The most recently added item is first, the least recently added
item is last.
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

45. Recently Used List Class
A recently-used-list is initially empty.
The most recently added item is first, the least recently added
item is last.
Items can be looked up by index, which counts from zero.
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

46. Recently Used List Class
A recently-used-list is initially empty.
The most recently added item is first, the least recently added
item is last.
Items can be looked up by index, which counts from zero.
Items in the list are unique, so duplicate insertions are moved
rather than added.
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

47. Recently Used List Class
A recently-used-list is initially empty.
The most recently added item is first, the least recently added
item is last.
Items can be looked up by index, which counts from zero.
Items in the list are unique, so duplicate insertions are moved
rather than added.
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

58. Recently Used List Class
A recently-used-list is initially empty.
The most recently added item is first, the least recently added
item is last.
Items can be looked up by index, which counts from zero.
Items in the list are unique, so duplicate insertions are moved
rather than added.
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

67. Recently Used List Class
A recently-used-list is initially empty.
The most recently added item is first, the least recently added
item is last.
Items can be looked up by index, which counts from zero.
Items in the list are unique, so duplicate insertions are moved
rather than added.
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

70. Recently Used List Class
A recently-used-list is initially empty.
The most recently added item is first, the least recently added
item is last.
Items can be looked up by index, which counts from zero.
Items in the list are unique, so duplicate insertions are moved
rather than added.
Develop a recently-used-list class to hold strings uniquely in Last-
In-First-Out order.

76. Refactor

77. to

78. this

79. That wasn’t so hard...

80. That wasn’t so hard...
...but what about testing the persistence layer?

81. You’ve got options

82. Mock the database layer
DBUnit
Codeception
You’ve got options

83. Mock the database layer
DBUnit
Codeception
You’ve got options
The

84. purist

85. way

86. Mock the database layer
DBUnit
Codeception
You’ve got options
The

87. purist

88. way
The

89. easy

90. way

91. Mock the database layer
DBUnit
Codeception
You’ve got options
The

92. purist

93. way
The

94. easy

95. way
The

96. even

97. easier

98. way

99. Mock Example
function testInsertDatabase()
{
$insertArray = array(
'name' = 'Miles',
);
// create a mock database
$mock = $this-getMockBuilder('Zend_Db_Adapter_Pdo_Mysql', array('insert'))
-disableOriginalConstructor()
-getMock();
// mock out the insert method
$mock
-expects($this-once())
-method('insert')
-with($insertArray);
// pass the database to the container
$container = new DIContainer():
$container-set('database', $mock);
// run the test
$user = new User();
$user-setName('Miles');
$user-save();
}
Not great because
• Requires Dependency Injection
• Can be fragile
• Complicated
But good because
• Super fast
• Not tied to database structure

100. DBUnit Example
public function testCanCreateNewUser()
{
$user = new User();
$user-setName('Miles');
$user-save();
$queryTable = $this-getConnection()-createTableQuery(
'users', 'SELECT * from users'
);
$expectedTable = $this-createFlatXmlDataSet(users-expected.xml)
-getTable('users');
$this-assertTableEquals($expectedTable, $queryTable);
}
Not great because
• Slow
• Can be fragile
• Tied to database structure
• Requires xml setup of expected results
But good because
• Tests are easy to write and read
• It’s obvious whats being tested

101. Codeception Example
?php
function testSavingUser()
{
$user = new User();
$user-setName('Miles');
$user-save();
$this-codeGuy-seeInDatabase('users',array('name' = 'Miles'));
}
?
Not great because
• Slow
• Tied to database structure
But good because
• Less fragile than DBUnit (no xml to maintain)
• Tests are easy to write and read
• It’s obvious whats being tested

102. When testing the DB...

103. When testing the DB...
Give each developer their own test database (preferably on
their own VM)

104. When testing the DB...
Give each developer their own test database (preferably on
their own VM)
DB tests are slow - move them outside the main suite or use
memory tables

105. When testing the DB...
Give each developer their own test database (preferably on
their own VM)
DB tests are slow - move them outside the main suite or use
memory tables
Use a tool like “Migrations” to keep databases in sync

106. UI Testing

107. UI Testing
PHPUnit with Selenium

108. UI Testing
PHPUnit with Selenium
Codeception

109. So, where do we go from here?

110. 1. Have a go
www.cyber-dojo.com

111. 2. Build up slowly

112. 2. Build up slowly
Start with one afternoon per week

113. 2. Build up slowly
Start with one afternoon per week
Try pair programming

114. 3. Motivate your team

115. 3. Motivate your team
Start a Coding Club / Kata

116. 3. Motivate your team
Start a Coding Club / Kata
[Get your boss to] buy some books

117. 3. Motivate your team
Start a Coding Club / Kata
[Get your boss to] buy some books
See

118. me

119. after

120. this

121. talk

122. 4. Get a CI server
Jenkins
Travis
CruiseControl

123. 5. Share

124. 5. Share
Attend public Katas

125. 5. Share
Attend public Katas
Forums IRC

126. Questions ?

127. Thank You
John Cleary
Lead Web Developer, DocNet
@TheRealBifter