Software Testing: Concepts and Operations

8 Test Generation Concepts

Whereas Chapters 9 and 10 explore strategies for test data generation, this chapter introduces concepts that help us streamline the discussion of test data generation, by reviewing such questions as the following: How does the target attribute that we are trying to achieve through the test influence test data generation? What requirements does the generated test data satisfy? What criteria can we deploy to generate test data? How do we assess the quality of generated test data (i.e., the extent to which the generated test data fulfills its requirements)? How do we measure test coverage, that is, the extent to which a test achieves its goal?

8.1 TEST GENERATION AND TARGET ATTRIBUTES

In Chapter 7, we have surveyed several different goals of a test operation, and several distinct attributes that a test operation may aim to establish. If we focus exclusively on test processes that aim to establish a functional property (dealing with input/output behavior, rather than performance or resource usage, for example) then we can identify the following possible categories:

1. Testing a program to establish correctness with respect to a specification (as in acceptance testing).
2. Testing a program to ensure that it computes its intended function (as in unit testing).
3. Testing a program to ensure that it is robust (i.e., that it behaves appropriately outside the domain of its specification).
4. Testing a program to ensure its safety (i.e., that even when it fails ...