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Wednesday, 3 October 2012

What is Equivalence Partitioning?

Equivalence Partitioning

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.


  1. I found some cool exam papers for ISTQB-BCS Certified Tester Foundation Level which has all the questions and answers and full explanation for Equivalence Partitioning @

  2. "Equivalence partitioning (also called Equivalence Class Partitioning or ECP[1]) is a software testing technique that divides the input data of a software unit into partitions of data from which test cases can be derived. In principle, test cases are designed to cover each partition at least once. This technique tries to define test cases that uncover classes of errors, thereby reducing the total number of test cases that must be developed.An advantage of this approach is reduction in the time required for testing a software due to lesser number of test cases"