Software Quality Assurance Practice Exam

Which black box testing type focuses on the boundaries between partitions of input values?

1. Boundary value analysis

2. Cause-effect graphing

3. Equivalence partitioning

4. Random sampling

The correct answer is: Boundary value analysis

Boundary value analysis is a black box testing technique that specifically targets the boundaries between different input value partitions. This method recognizes that errors are more likely to occur at the edges of input ranges rather than within the ranges themselves. For instance, if a program accepts input values from 1 to 100, boundary value analysis would specifically test the values 1, 100, and also values just outside this range, like 0 and 101, to ensure proper handling of these edge cases. In this testing strategy, the assumption is made that the most significant defects often arise at the boundaries, making it crucial to test those points thoroughly. By focusing on these boundary values, testers can effectively identify potential software failures that might not be revealed by testing within the partitions alone. Other techniques mentioned, such as equivalence partitioning, while related, do not focus solely on the boundary conditions. They look at grouping inputs into partitions where the system should behave similarly. Meanwhile, cause-effect graphing and random sampling approach testing from different angles and do not explicitly hone in on these boundaries. Thus, boundary value analysis is the most relevant type for this question's emphasis on defining and testing at the boundaries.