Equivalence Partitioning Tutorial

Definition of Equivalence Partitioning

Equivalence Partitioning is a black-box testing technique (basic test-design technique) that splits the input domain into classes of data. From this data, we can derive test cases.

Test-case design with the help of equivalence partitioning technique has two steps:

1) Identifying the equivalence classes.
2) Defining the test cases.

Example 1 of Equivalence Partitioning

Problem:-

The program reads three integer values from an input dialog. The three values represent the lengths of the sides of a triangle. The program displays a message that states whether the triangle is scalene, isosceles, or equilateral. Remember that a scalene triangle is one where no two sides are equal, whereas an isosceles triangle has two equal sides, and an equilateral triangle has three sides of equal length. Moreover, the angles opposite the equal sides in an isosceles triangle also are equal (it also follows that the sides opposite equal angles in a triangle are equal), and all angles in an equilateral triangle are equal.
(Source: http://www.amazon.com/Art-Software-Testing-Glenford-Myers/dp/0471043281)


Solution:-

As seen in the definition above we have to identify equivalence classes and define test cases based on those classes.

Equivalence Classes for the triangle problem

More solutions to the triangle problem

Solution 1

Solution 2

Solution 3

Solution 4

Example 2 of Equivalence Partitioning

The specifications for a application software system for authenticating expenses claim for motel accommodation for one night includes the following requirements:

The upper limit is $100 for accommodation expenses claims.
Any claims above $100 should be rejected and should cause an error message to be displayed.
Expense amounts should be greater than $0 and an error message should be displayed otherwise.