Equivalence class:

Equivalence class is a concept in software testing that groups inputs or values into sets that are expected to behave similarly. This is a technique used to reduce the number of test cases and to ensure that each test case is unique and effective.

Why are equivalence classes used?

Equivalence classes are used in software testing to ensure that each test case is unique and effective. It helps in reducing the number of test cases required to test a system. Instead of testing each input or value individually, it groups them into sets that are expected to behave similarly.

How are equivalence classes created?

Equivalence classes are created by grouping inputs or values into sets that are expected to behave similarly. These sets are called equivalence classes. The inputs or values within an equivalence class are expected to produce the same result when tested.

Example of equivalence classes:

For example, let's consider a system that accepts a numeric input between 1 and 10. We can create the following equivalence classes:

- Inputs between 1 and 5
- Inputs between 6 and 10
- Inputs outside the range of 1 to 10

All inputs within the same equivalence class are expected to behave similarly. So, we can test one input from each equivalence class to ensure that the system is working as expected.

Advantages of equivalence classes:

- It helps in reducing the number of test cases required to test a system.
- It ensures that each test case is unique and effective.
- It helps in identifying defects or issues within the system.

Disadvantages of equivalence classes:

- It may not cover all possible scenarios.
- It may not cover edge cases that are outside of the equivalence classes.
- It may be difficult to create equivalence classes for complex systems.