határértéktesztelésre

Boundary value testing, known in Hungarian as határértéktesztelés, is a software testing technique that focuses on the values at the extremes of input ranges. The principle behind the method is that errors often occur at the boundaries of input domains rather than within the interior. By systematically examining values near the lower and upper limits, as well as just outside these limits, testers can uncover faults that might remain hidden during typical value testing.

The technique operates by identifying the valid input range for a given variable or function, then selecting test cases that include the smallest valid value, the largest valid value, the value immediately below the lower limit, and the value immediately above the upper limit. For example, if a program accepts integers from 1 to 100, test cases would typically include 1, 100, 0, and 101. Additional boundary values, such as “one more than the largest value” or “one less than the smallest value,” are often included to check for off‑by‑one errors and overflow bugs.

Boundary value testing is particularly effective for programs that depend on numeric calculations, array indexing, and loop conditions. It is also useful for verifying input validation logic and ensuring that error messages are correctly triggered when limits are exceeded. Compared to equivalence partitioning, boundary tests target specific points that are more likely to produce defects, while still covering a representative subset of the input space.

Limitations of the method arise when the program’s behavior is not solely dependent on numerical input ranges, for instance in complex multi‑parameter systems or in cases where internal state dictates boundary behavior. In such situations, boundary tests should be combined with other techniques, such as decision table testing or state transition testing, to achieve sufficient coverage.

Overall, határértéktesztelés remains a cornerstone of systematic software quality assurance, providing a simple yet powerful approach to detect errors that can compromise reliability and user safety.