Stability Testing is the testing process to determine the ability of the software product to perform its required functions under specified conditions for a stated period of time, or for a certain number of operations. In other words, it is a testing of the stability of a software product.

In this case, the most privilege goes to the absence of memory leaks, unexpected failures of the application or a system, restarts of servers under load, and other aspects that affect stability.

It is a part of non-functional testing conducted as part of performance testing and sometimes can be referred as endurance testing.

The meaning of stability testing implies that - it is a software testing technique adopted to verify if an application can perform well without a break, within or just above the acceptable period of time.

Stability testing is not mandatory. But if an application, that wasn’t tested in stability, began to have a large number of users and should run for months without restarting, a number of problems can occur.

Possible error can be faced:

• the system slows down
• the system encounters functionality problems
• the system shows weird behavior
• the system crashes altogether

In the software development, stability and reliability could be confused, but they are different.

Reliability is the degree to which an experiment, test, or any measuring procedure yields the same result on repeated basis. In other words, it is the process of testing to determine the ability of the software product to perform its required functions under stated conditions for a specified period of time, or for a specified number of operations.

Stability is a time-varying attribute which can be judged by studying the performance of the power system under a particular set of conditions. To determine stability, a measure or test is repeated on the same subjects at a future date. Results are compared and correlated with the initial test to give a measure of stability.

Reasons to do stability testing:

• To provide confidence in the work of your system.
• To ensure that the system can work without restarting for a long period of time even if there are lots of users.
• To check that the system doesn’t have any memory leaks, unexpected failures or other aspects that affect stability.
• To monitor the effectiveness of the system under test
•  To test system stability under stress

It plays an important role in the development of a product as it is used to determine the limitations of a software product under test before it is released, or the areas of more improvement before the product launch.

Occasionally, on some conditions, stability testing and stress testing are combined, checking not only stability but also the ability of an application to withstand tough conditions and heavy loads for a long time.

Examples of stability testing technique.

The stability testing of an online shopping portal, except the behavior of the system, will check how the website acts when:

• A high amount of data entered at peak time.
• A number of hits occur at a certain specific time.
• The responsiveness of the system in general.
• A page load issues at the same time and others.

Another example: a CPU test is a popular form of stability test. It checks processor stability and also monitors its performance while the processor's workload is increased.

In conclusion, we can say that stability testing is the ability of the product to continue to function, over time and over its full range of use, without failing or causing failure.