What does equivalent partitioning focus on during testing?

Equivalent partitioning is a testing technique used to reduce the number of test cases required to test a system while ensuring that all potential scenarios are covered effectively. It achieves this by dividing the input data of the software into partitions or equivalence classes, where each partition is expected to behave similarly.

By focusing on checking ranges and lists of values, equivalent partitioning allows testers to identify a set of values that represent a broader category of input. For instance, if a system accepts age as input, instead of testing every individual age, a tester might choose representative values from defined ranges (such as 0-17, 18-64, and 65+) to validate that the system behaves correctly for all ages within those ranges. This reduces redundancy in testing while ensuring comprehensive coverage of input scenarios.

This technique is particularly beneficial in functional testing, ensuring that the application works as intended for various types of input without the need to exhaustively iterate through every single value. Therefore, focusing on checking ranges and lists of values aligns perfectly with the principles of equivalent partitioning.