Equivalence Partitioning

Equivalence partitioning

Equivalence partitioning (EP) is a blackbox testing technique. This technique is very common and mostly used by all the testers informally. Equivalence partitions are also known as equivalence classes.

As the name suggests Equivalence partitioning is to divide or to partition a set of test conditions into sets or groups that can be considered same by the software system.

As you all know that exhaustive testing of the software is not feasible task for complex software’s so by using equivalence partitioning technique we need to test only one condition from each partition because it is assumed that all the conditions in one partition will be treated in the same way by the software. If one condition works fine then all the conditions within that partition will work the same way and tester does not need to test other conditions or in other way if one condition fails in that partition then all other conditions will fail in that partition.


These conditions may not always be true however testers can use better partitions and also test some more conditions within those partitions to confirm that the selection of that partition is fine.

Example: 
Assume that the application accepts an integer in the range 100 to 999
Valid Equivalence Class partition: 100 to 999 inclusive.
Non-valid Equivalence Class partitions: less than 100, more than 999, decimal numbers and alphabets/non-numeric characters.