Boundary-Value Analysis is a black-box testing technique that focuses on testing the boundaries or extreme values of input or output conditions. It involves selecting test cases at or just beyond the boundaries of equivalence classes.
The key idea behind Boundary-Value Analysis is that errors often occur at the boundaries of input ranges rather than within the ranges themselves. By testing the boundary values, it is possible to identify potential issues related to boundary conditions, such as off-by-one errors, boundary-related calculations, and input validation problems.
Boundary-Value Analysis is particularly useful in situations where input ranges are defined, such as numeric ranges, date ranges, or ranges of valid input values. By testing the boundary values, both within and just beyond the specified ranges, you can increase the chances of identifying defects that may occur at those boundaries.
When to apply Boundary-Value Analysis:
Boundary-Value Analysis can be applied in the following scenarios:
Input Range Validation: When there are defined input ranges or limits, such as age, quantity, or monetary values, boundary values should be tested to ensure the system handles them correctly.
Calculation or Comparison Scenarios: When calculations or comparisons are performed on input values, testing the boundary values helps identify issues related to boundary conditions, rounding errors, or precision problems.
Input Conditions with Constraints: When input conditions have specific constraints or business rules associated with them, testing the boundaries of those constraints can help ensure the system handles them appropriately.
Error-Prone Scenarios: When there is a history of errors or known issues occurring at the boundaries of input ranges, applying Boundary-Value Analysis can help identify and prevent such issues.