Equivalence Partitioning Test Case Design Technique

 

Equivalence Partitioning Test Case Design:

Equivalence partitioning is a software testing technique that is used to divide the input data of a system into different partitions, called equivalence classes. The goal of equivalence partitioning is to create test cases that will effectively exercise the system and detect defects.

The idea behind equivalence partitioning is that the system should behave the same way for all inputs within the same partition. By testing a representative sample of inputs from each partition, it is possible to achieve good test coverage with a relatively small number of test cases.

Design Test case using Equivalence Partitioning:

The process of equivalence partitioning starts by identifying the input domain of the system and dividing it into equivalence classes. Each class should be defined by a set of constraints and should include similar inputs. 

For example, if a system accepts integers as input, one equivalence class might be all positive integers, another class could be all negative integers and zero, and another class could be all non-integers.

Once the classes are defined, test cases are designed to test the system with inputs from each class. These test cases should be chosen in a way that will effectively exercise the system and detect defects. For example, a boundary value test case should be selected for each class, such as the minimum and maximum values, as well as values just above and below these limits.

Equivalence partitioning is an effective technique for creating test cases that will achieve good test coverage and detect defects. It is especially useful for testing systems that have a large input domain or that accept a wide range of input values.

Example of Equivalence Partitioning:

Example of how equivalence partitioning can be used to design test cases for a simple login system:

The input domain for the login system is a combination of a username and a password.

• The first equivalence class is valid username and password combinations. Test cases should be designed to test the system with different valid username and password combinations, such as alphanumeric combinations, special characters, and minimum and maximum lengths.

• The second equivalence class is invalid username and password combinations. Test cases should be designed to test the system with different invalid username and password combinations, such as incorrect username and password, empty username or password, and username or password that exceeds the maximum length.

• The third equivalence class is invalid username or invalid password. Test cases should be designed to test the system with different invalid username or invalid password combinations, such as incorrect username and valid password, valid username and incorrect password, and invalid characters in the username or password.

• The fourth equivalence class is empty username and password. Test cases should be designed to test the system with empty username and password input.

In this example, the test cases designed from the equivalence partitioning method will cover all possible input scenarios for the login system, which will increase the chances of detecting defects and improve the overall quality of the system.