Developer Testing

Alexander Tarlinder wrote his first computer program around the age of ten, sometime in the early nineties. It was a simple, text-based role playing game for the Commodore 64. It had lots of GOTO statements and an abundance of duplicated code. Still, to him, this was the most fantastic piece of software ever conceived, and an entry point to his future career. Twenty-five years later, Alexander still writes code and remains a developer at heart. Today, his professional career stretches over 15 years, a time during which he has shouldered a variety of roles: developer, architect, project manager, ScrumMaster, tester, and agile coach. In all these roles, he has gravitated towards sustainable pace, craftsmanship, and attention to quality, and he eventually got test infected around 2005. In a way, this was inevitable, since many of his projects involved programming money somehow (in the banking and gaming industry), and he always felt that he could do more to ensure the quality of his code before handing it over to someone else. Presently, Alexander seeks roles that allow him to influence the implementation process on a larger scale. He combines development projects with training and coaching, and he shares technical and nontechnical aspects of developer testing and quality assurance in conferences and local user groups meetings. Normal 0 false false false EN-US X-NONE X-NONE

Chapter 1: Developer Testing 1

Developers Test 1

Developer Testing Activities 2

What Developers Usually Dont Do 5

Defining Developer Testing 6

Developer Testing and the Development Process 7

Summary 8

Chapter 2: Testing Objectives, Styles, and Roles 9

Testing and Checking 9

Testing Objectives 10

Testing Styles 11

Your Quality Assurance and Developer Testing 18

Summary 19

Chapter 3: The Testing Vocabulary 21

Errors, Defects, Failures 22

White Box and Black Box Testing 22

Classifying Tests 23

The Agile Testing Quadrants 32

Some Other Types of Testing 33

Summary 36

Chapter 4: Testability from a Developers Perspective 37

Testable Software 37

Benefits of Testability 39

Testability Defined 43

Summary 55

Chapter 5: Programming by Contract 57

Contracts Formalize Constraints 57

Implementing Programming by Contract 60

Enforcing Contracts 62

Summary 65

Chapter 6: Drivers of Testability 67

Direct Input and Output 68

Indirect Input and Output 68

State 70

Temporal Coupling 71

Data Types and Testability 72

Domain-to-Range Ratio 77

Summary 78

Chapter 7: Unit Testing 79

Why Do It? 79

What Is a Unit Test? 81

The Life Cycle of a Unit Testing Framework 83

Naming Tests 85

Structuring Tests 88

Assertion Methods 89

Testing Exceptions 99

Behavior-driven DevelopmentStyle Frameworks 102

Summary 105

Chapter 8: Specification-based Testing Techniques 107

Equivalence Partitioning 107

Boundary Value Analysis 110

Edge Cases and Gotchas for Some Data Types 111

State Transition Testing 113

Decision Tables 115

Summary 116

Chapter 9: Dependencies 119

Relations between Objects 119

System Resource Dependencies 125

Dependencies between Layers 129

Dependencies across Tiers 132

Summary 133

Chapter 10: Data-driven and Combinatorial Testing 135

Parameterized Tests 138

Theories 139

Generative Testing 141

Combinatorial Testing 145

Summary 149

Chapter 11: Almost Unit Tests 151

Examples 152

Impact 156

Summary 157

Chapter 12: Test Doubles 159

Stubs 159

Fakes 162

Mock Objects 164

Spies 170

Dummies 171

Verify State or Behavior? 173

Summary 176