Equivalence partitioning uses a model of the component that partitions the input and output values of the component. The input and output values are derived from the specification of the component's behaviour.
The model shall comprise partitions of input and output values. Each partition shall contain a set or range of values, chosen such that all the values can reasonably be expected to be treated by the component in the same way (i.e. they may be considered 'equivalent'). Both valid and invalid values are partitioned in this way.Test cases shall be designed to exercise partitions. A test case may exercise any number of partitions. A test case shall comprise the following:
- the input(s) to the component:
- the partitions exercised:
- the expected outcome of the test case.
Test cases are designed to exercise partitions of valid values, and invalid input values. Test cases may also be designed to test that invalid output values cannot be induced.