Equivalence partitioning

                 Equivalence partitioning 

Equivalence partitioning is a Test Case Design Technique to divide the input data of software into different equivalence data classes. Test cases are designed for equivalence data class. The equivalence partitions are frequently derived from the requirements specification for input data that influence the processing of the test object. A use of this method reduces the time necessary for testing software using less and effective test cases.

Equivalence Partitioning = Equivalence Class Partitioning = ECP

 It can be used at any level of software for testing and is preferably a good technique to use first. In this technique, only one condition to be tested from each partition. Because we assume that, all the conditions in one partition behave in the same manner by the software. In a partition, if one condition works other will definitely work. Likewise we assume that, if one of the condition does not work then none of the conditions in that partition will work.

Equivalence partitioning is a testing technique where input values set into classes for testing.

Valid Input Class = Keeps all valid inputs.

Invalid Input Class = Keeps all Invalid inputs.

 Example of Equivalence Class Partitioning?

A text field permits only numeric characters

Length must be 6-10 characters long

Partition according to the requirement should be like this:

While evaluating Equivalence partitioning, values in all partitions are equivalent that’s why 0-5 are equivalent, 6 – 10 are equivalent and 11- 14 are equivalent.

                At the time of testing, test 4 and 12 as invalid values and 7 as valid one.

It is easy to test input ranges 6–10 but harder to test input ranges 2-600. Testing will be easy in the case of lesser test cases but you should be very careful. Assuming, valid input is 7. That means, you belief that the developer coded the correct valid range (6-10).