Which of the following statements are true for the equivalence partitioning test technique?
1. Divides possible inputs into classes that have the same behavior.
2. Can be used to create both positive and negative test cases.
3. Makes use of only positive test cases for the equivalence partitions.
4. Must always include at least two values from every equivalence partition.
5. Can be used only for input testing.

In Software Design, there needs to be methodology for testing techniques satisfactorily. Equivalence testing is one of these and equivalence partitioning also known as Equivalence Class Partitioning. Inputs to the software or system are divided into groups.

The grouping is arranged so that inputs expected to exhibit similar behaviour are together. Therefore, option 1 in the question set is correct. Option 2 is also correct because if all tests were positive there would be no point in testing. Therefore Option 3 must be incorrect. Option 4 is questionable.

By definition a 'group' would have more than one entry. However, logically it should be possible for an item not to fit into any other group and therefore need to be tested as a group in itself. Option 5 is wrong because input and output are tested.

I & ii-we know statement i must be true because it appears in every answer (so if youd forgotten what equivalence partitions are, this would give you a clue). statement ii is true, because we can have both valid and invalid partitions (i.e. positive and negative tests). statement iii is false because it contradicts ii. statement iv is false, because one value per partition is enough. statement v is false because the definition in the glossary mentions both input and output domains, so the answer is a.