In this presentation, we discussed what Test-Driven Development(TDD) is, how to get started with TDD, work through an example, and discuss how to get started in your application.

1. Getting Started with Test-
Driven Development
Scott Keck-Warren
@scottKeckWarren
PHPdevelopers.tv

2. Scott Keck-Warren
• Director of Technology at
WeCare Connect
• Host at
http://PHPdevelopers.tv

3. What Are You Going to Learn?
1. What Is Test-Driven Development
2. Why You Should Be Using Test-
Driven Development
3. How To Do Test-Driven Development
4. How To Get Started On Your Project
5. Common Gotchas

4. What is Test-Driven
Development?

5. What is Test-Driven
Development?
• Abbreviated TDD
• Test-first software development process
• Create suite of automated tests
• Short cycles of 5 phases
• < Minute

6. What is Test-Driven
Development?
• “Rediscovered” by Kent Beck
• “Test Driven Development: By
Example”

7. What is Test-Driven
Development?
• “Best” for greenfield
• Works well for brownfield
• Check out “Working Effectively
with Legacy Code” by Michael
Feathers for brownfield

8. Why You Should Be
Using TDD

9. TDD Gives Us Confidence
to Make Changes

10. Why You Should Be Using
TDD
• 4PM on before long weekend
• Boss asks for “little” change
• What do you do?
Photo by Yan Krukov from Pexels

11. Why You Should Be Using
TDD
• TDD gives us confidence
• Automated Tests Pass
• Push to Production
• Go Have Fun
Photo by Min An from Pexels

12. How Do You Use Test
Driven Development?

13. How Do You Use Test Driven
Development?
• 5 Phases
• Each < 10 lines of code modified

14. #1. Add A New Test
• Write a failing test
• Should be succinct
• Goal: how does a single
change affect our code

15. # 2. Run All Tests and See
The New One Fail
• Make sure the
new test fails

16. # 2. Run All Tests and See
The New One Fail
• Run All Tests?

17. #3. Make A Little Change
• Smallest amount of
change to get test to pass
• Doesn’t need to be perfect
• “Perfect” comes later

18. #4. Run All Tests and See
Them All Succeed
• Make sure all the tests
succeed
• If not jump back to phase
#3

19. #5. Refactor to Remove
Duplication
• Refactor: Restructure so
as to improve operation
without altering
functionality.

20. #5. Refactor to Remove
Duplication
• Are the
method/class/variables
easy to read?
• Do they express
intent?
• Will future me
understand them?

21. #5. Refactor to Remove
Duplication
• Can we move logic into
the superclass?
• Can we move logic into
a shared trait?

22. Repeat

23. Red, Green, Refactor
• 3 Phase Version
• Red -> Failing
• Green -> Passing
• Refactor

24. PHPUnit

25. PHPUnit
• Test Framework
• De Facto Testing Framework
for PHP
• Written by Sebastian
Bergmann
• All tests are written in PHP
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26. PHPUnit
• Organization is easy
• All test files inside a tests
folder
• A test is a PHP class method
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27. PHPUnit
public function testAStringCausesIsEmptyToReturnFalse(): void
{
$item = new SuperString('Test Data');
$this->assertFalse($item->isEmpty());
}

28. PHPUnit
public function testAStringCausesIsEmptyToReturnFalse(): void
{
$item = new SuperString('Test Data');
$this->assertFalse($item->isEmpty());
}
/**
* @test
*/
public function aStringCausesIsEmptyToReturnFalse(): void
{
$item = new SuperString('Test Data');

29. PHPUnit
•Each test contains one or more asserts
$this->assertFalse($value);
$this->assertEquals($expectedValue, $value);
$this->assertGreaterThan($number, $value);

30. PHPUnit
• A PHP class groups similar tests together
• Ideally a test class for each application class with logic
• A test class for common initial conditions
• Each class ends with “Test”

31. PHPUnit
• Installed using composer
• Can install globally or per project
• Per project is the way to go

32. PHPUnit
• Command line tool
• Super powerful
• phpunit
• phpunit tests/Unit/SuperStringTest.php
• phpunit —filter User
• PHPUnit + IDE = More efficient

33. PHPUnit
• From the command line:
• ./vendor/bin/phpunit tests/Unit/SuperStringTest.php

34. SuperString

35. SuperString
class SuperString
{
private $string = null;
public function __construct(string $string)
{
$this->string = $string;
}
}

36. isEmpty()

37. isEmpty() - Add Test
• Create tests/Unit/SuperStringTest.php

38. isEmpty() - Add Test
<?php

39. isEmpty() - Add Test
<?php
namespace TestsUnit;
class SuperStringTest
{

40. isEmpty() - Add Test
<?php
namespace TestsUnit;
use PHPUnitFrameworkTestCase;
class SuperStringTest extends TestCase
{

41. isEmpty() - Add Test
<?php
namespace TestsUnit;
use PHPUnitFrameworkTestCase;
class SuperStringTest extends TestCase
{
public function testBlankStringCausesIsEmptyToReturnTrue(): void
{

42. isEmpty() - Add Test
<?php
namespace TestsUnit;
use AppSuperString;
use PHPUnitFrameworkTestCase;
class SuperStringTest extends TestCase
{
public function testBlankStringCausesIsEmptyToReturnTrue(): void
{
$item = new SuperString('');

43. isEmpty() - Add Test
<?php
namespace TestsUnit;
use AppSuperString;
use PHPUnitFrameworkTestCase;
class SuperStringTest extends TestCase
{
public function testBlankStringCausesIsEmptyToReturnTrue(): void
{
$item = new SuperString('');

44. isEmpty() - Run Tests

45. isEmpty() - Run Tests

46. isEmpty() - Make A Change
// in SuperString
public function isEmpty(): bool
{
return true;
}
// in SuperString
public function isEmpty(): bool
{
return mb_strlen($this->string) == 0;
}

47. isEmpty() - Make A Change
// in SuperString
public function isEmpty(): bool
{
return true;
}

48. isEmpty() - Run Tests

49. isEmpty() - Refactor

50. !isEmpty()

51. !isEmpty() - Add Test
// in SuperStringTest
public function testBlankStringCausesIsEmptyToReturnTrue(): void
{
$item = new SuperString('');
$this->assertTrue($item->isEmpty());
}

52. !isEmpty() - Add Test
// in SuperStringTest
public function testBlankStringCausesIsEmptyToReturnTrue(): void
{
$item = new SuperString('');
$this->assertTrue($item->isEmpty());
}
public function testAStringCausesIsEmptyToReturnFalse(): void
{
$item = new SuperString('Test Data');
$this->assertFalse($item->isEmpty());
}

53. !isEmpty() - Run Tests

54. !isEmpty() - Make a Change
// in SuperString
public function isEmpty(): bool
{
return true;
}

55. !isEmpty() - Make a Change
// in SuperString
public function isEmpty(): bool
{
return mb_strlen($this->string) == 0;
}

56. !isEmpty() - Run Tests

57. !isEmpty() - Refactor

58. isNotEmpty()

59. isNotEmpty() - Add Test
// in SuperStringTest
public function testBlankStringCausesIsNotEmptyToReturnFalse(): void
{
$item = new SuperString('');
$this->assertFalse($item->isNotEmpty());
}

60. isNotEmpty() - Run Tests

61. isNotEmpty() - Make A
Change
// in SuperString
public function isNotEmpty(): bool
{
return mb_strlen($this->string) != 0;
}

62. isNotEmpty() - Run Tests

63. isNotEmpty() -
Refactor

64. isNotEmpty() - Refactor
// in SuperString
public function isEmpty(): bool
{
return mb_strlen($this->string) == 0;
}
public function isNotEmpty(): bool
{
return mb_strlen($this->string) != 0;
}

65. isNotEmpty() - Refactor
// in SuperString
public function isEmpty(): bool
{
return mb_strlen($this->string) == 0;
}
public function isNotEmpty(): bool
{
return mb_strlen($this->string) != 0;
}

66. isNotEmpty() - Refactor
// in SuperString
public function isEmpty(): bool
{
return mb_strlen($this->string) == 0;
}
public function isNotEmpty(): bool
{
return mb_strlen($this->string) != 0;
}

67. isNotEmpty() - Refactor
// in SuperString
public function isEmpty(): bool
{
return $this->length() == 0;
}
public function isNotEmpty(): bool
{
return $this->length() != 0;
}

68. isNotEmpty() - Refactor
// in SuperString
public function isEmpty(): bool
{
return mb_strlen($this->string) == 0;
}
public function isNotEmpty(): bool
{
return mb_strlen($this->string) != 0;
}

69. isNotEmpty() - Refactor
// in SuperString
public function isEmpty(): bool
{
return mb_strlen($this->string) == 0;
}
public function isNotEmpty(): bool
{
return !$this->isEmpty();
}

70. isNotEmpty() - Refactor

71. Integration Tests

72. Integration Tests
Unit
Single Class

73. Integration Tests
Unit ?
Single Class Multiple Classes

74. Integration Tests
Unit Integration
Single Class Multiple Classes

75. Integration Tests
Unit Integration
Single Class Multiple Classes
Faster Slower

76. Integration Tests
Unit Integration
Single Class Multiple Classes
Faster Slower
Targeted Broad

77. Integration Tests
public function testCanAccessCategoriesRoute(): void
{
$response = $this->get('/categories');
$response->assertOk();
}

78. How To Get Started
On Your Project

79. Getting Started By Yourself
1. Just start doing it
2. Talk to manager first
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80. Getting Started With
Your Team

81. Getting Started With Your
Team
1. Get management buy in
2. Get everyone using TDD
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82. Getting Started With Your
Team
1. Book recommendations
1. “Test Driven
Development: By
Example” by Kent Beck
2. “Working Effectively with
Legacy Code” by Michael
Feathers
Photo by Liza Summer from Pexels

83. Getting Started With Your
Team
1. Basic Training on TDD with
your code base
2. Code Reviews with TDD as
the keystone
3. Pair Programming
Photo by Christina Morillo from Pexels

84. Common Gotchas

85. Neglecting to Run
Tests

86. Creating Too Many
Tests At Once

87. Creating Large Tests

88. Creating Trivial Tests

89. Review

90. Review
• TDD: test-first software development process
• Five short phases
• Each of the phases happens very quickly
• Don’t neglect to refactor

91. Review

92. Review
• Use PHPUnit
• Write clear and concise tests

93. Review
• It may seem complicated/confusing but just start

94. Review
• Avoid
• Neglecting to Run Tests
• Creating Too Many Tests At Once
• Creating Large Tests
• Creating Trivial Tests

95. Questions & More
Information
@scottKeckWarren
http://PHPdevelopers.tv
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