Final answer:
Equivalence partitioning is a testing technique that divides the input domain into smaller, equivalent subdomains to minimize test cases while ensuring coverage. It includes both valid and invalid input scenarios to thoroughly test software behavior.
Step-by-step explanation:
Equivalence partitioning is a software testing technique which subdivides the input domain into a relatively small number of equivalent subdomains. The idea behind equivalence partitioning is that by testing a single representative input from each partition deemed equivalent, you can determine the expected results for all other inputs in that partition. This approach can drastically reduce the number of test cases that must be developed while still ensuring a high level of coverage over the input domain. In practice, equivalence partitions are usually defined such that they capture both valid and invalid input scenarios to ensure that the software behaves correctly across a variety of input conditions.