Ääripäätestaus

Ääripäätestaus, also known as extreme value testing or boundary value analysis, is a software testing technique where test cases are designed to cover the extreme input values or boundary conditions of a given input domain. The core principle behind this method is that errors are most likely to occur at the edges of the input ranges, rather than in the middle.

The process involves identifying the valid and invalid ranges for each input field. For a given input field, the test designer selects values that are at the minimum and maximum of the valid range, as well as values just below the minimum and just above the maximum of the valid range. For instance, if an input field accepts values between 1 and 100, the boundary values to test would be 0, 1, 100, and 101.

Ääripäätestaus is particularly effective for numerical inputs, but it can also be applied to other data types, such as strings (e.g., testing with empty strings, very long strings) or dates (e.g., testing with the earliest and latest possible dates). This technique helps in uncovering defects that might be missed by other testing methods, as it systematically targets the areas where program logic is often most complex and prone to errors. It is a form of black-box testing, meaning the internal structure of the code is not considered during test case design.