The essence of domain testing is that you partition a domain (a set of values) into subdomains (equivalence classes) and select representatives of each subdomain for your tests.
• Equivalence class analysis is about similarity. Two values belong in the same class if they are so similar the program will treat them the same way.
Testing with only one or two representatives of each class allows you to substantially reduce the number of tests.
• Picking representatives is about risk. As used in this book, a risk is a way the program can fail. Look for a value that is a little more likely to cause the program to fail than the others. This value is often at the boundary of a class. Picking powerful ...