James Whittaker has spent his career in software testing and has left his mark on many aspects of the discipline. He was a pioneer in the field of model-based testing, where his Ph.D. dissertation from the University of Tennessee stands as a standard reference on the subject. His work in fault injection produced the highly acclaimed runtime fault injection tool Holodeck, and he was an early thought leader in security and penetration testing. He is also well regarded as a teacher and presenter, and has won numerous best paper and best presentation awards at international conferences. While a professor at Florida Tech, his teaching of software testing attracted dozens of sponsors from both industry and world governments, and his students were highly sought after for their depth of technical knowledge in testing.

Dr. Whittaker is the author of How to Break Software and its series follow-ups How to Break Software Security (with Hugh Thompson) and How to Break Web Software (with Mike Andrews). After ten years as a professor, he joined Microsoft in 2006, and left in 2009 to join Google as the Director of Test Engineering for the Kirkland and Seattle offices. He lives in Woodinville, Washington, and is working toward a day when software just works.

Foreword by Alan Page xv

Preface xvii

Chapter 1 The Case for Software Quality 1

The Magic of Software 1

The Failure of Software 4

Conclusion 9

Exercises 9

Chapter 2 The Case for Manual Testing 11

The Origin of Software Bugs 11

Preventing and Detecting Bugs 12

Manual Testing 14

Conclusion 19

Exercises 20

Chapter 3 Exploratory Testing in the Small 21

So You Want to Test Software? 21

Testing Is About Varying Things 23

User Input 23

What You Need to Know About User Input 24

How to Test User Input 25

State 32

What You Need to Know About Software State 32

How to Test Software State 33

Code Paths 35

User Data 36

Environment 36

Conclusion 37

Exercises 38

Chapter 4 Exploratory Testing in the Large 39

Exploring Software 39

The Tourist Metaphor 41

“Touring” Tests 43

Tours of the Business District 45

Tours Through the Historical District 51

Tours Through the Entertainment District 52

Tours Through the Tourist District 55

Tours Through the Hotel District 58

Tours Through the Seedy District 60

Putting the Tours to Use 62

Conclusion 63

Exercises 64

Chapter 5 Hybrid Exploratory Testing Techniques 65

Scenarios and Exploration 65

Applying Scenario-Based Exploratory Testing 67

Introducing Variation Through Scenario Op