What is an equivalence partitioning?

Equivalence Partitioning is a test design method where the set of all possible input data is divided into equivalence classes (partitions). It is assumed that the program will behave the same within each class, so it is sufficient to test one representative from each class.

For example, if a field accepts numbers from 1 to 100, classes can be distinguished as:

• valid values (1–100),
• values less than 1 (invalid),
• values greater than 100 (invalid).

Testing one value from each class effectively covers different scenarios without redundancy.