Reliability Testing is a testing technique that relates to test the ability of a software to function and given environmental conditions that helps in uncovering issues in the software design and functionality. It is defined as a type of software testing that determines whether the software can perform a failure free operation for a specific period of time in a specific environment. It ensures that the product is fault free and is reliable for its intended purpose.

The objective of reliability testing is :

• To find the perpetual structure of repeating failures.
• To find the number of failures occurring is the specific period of time.
• To discover the main cause of failure.
• To conduct performance testing of various modules of software product after fixing defects.

There are three types of reliability testing :

Following three steps are involved in this testing :

• Each function in the software should be executed at least once.
• Interaction between two or more functions should be reduced.
• Each function should be properly executed.

Regression testing is basically performed whenever any new functionality is added, old functionalities are removed or the bugs are fixed in an application to make sure with introduction of new functionality or with the fixing of previous bugs, no new bugs are introduced in the application.

Load testing is carried out to determine whether the application is supporting the required load without getting breakdown. It is performed to check the performance of the software under maximum work load.

The study of reliability testing can be divided into three categories :

• Modelling
• Measurement
• Improvement