Introduction to Software Testing

The purpose of this book is to teach software engineers how to test. This knowledge is useful whether you are a programmer who needs to unit test your own software, a full-time tester who works mostly from requirements at the user level, a manager in charge of testing or development, or any position in between. As the software industry moves into the second decade of the 21st century, software quality is increasingly becoming essential to all businesses and knowledge of software testing is becoming necessary for all software engineers.

Today, software defines behaviors that our civilization depends on in systems such as network routers, financial calculation engines, switching networks, theWeb, power grids, transportation systems, and essential communications, command, and control services. Over the past two decades, the software industry has become much bigger, is more competitive, and has more users. Software is an essential component of exotic embedded applications such as airplanes, spaceships, and air traffic control systems, as well as mundane appliances such as watches, ovens, cars, DVD players, garage door openers, mobile phones, and remote controllers. Modern households have hundreds of processors, and new cars have over a thousand; all of them running software that optimistic consumers assume will never fail! Although many factors affect the engineering of reliable software, including, of course, careful design and sound process management, testing is the primary way industry evaluates software during development. The recent growth in agile processes puts increased pressure on testing; unit testing is emphasized heavily and test-driven development makes tests key to functional requirements. It is clear that industry is deep into a revolution in what testing means to the success of software products.

Fortunately, a few basic software testing concepts can be used to design tests for a large variety of software applications. A goal of this book is to present these concepts in such a way that students and practicing engineers can easily apply them to any software testing situation.

This textbook differs from other software testing books in several respects. The most important difference is in how it views testing techniques. In his landmark book Software Testing Techniques, Beizer wrote that testing is simple—all a tester needs to do is “find a graph and cover it.”