What is Spike Testing?

Spike testing is usually done to estimate the weakness of an application and see the dramatic behavior of the system when a sudden increment or decrements in the load by a user. Spike testing is mainly done to see how the system reacts with unexpected rise and fall of the load. It is also called Data volume testing.

There are different cases that could be considered during testing in order to make sure that application handle efficiently against unexpected load. One case is not to allow the application to use more number of users, so that system does not undergo heavy load at all. This can prevent more number of people from entering into the system and protect the system from any excessive load. Another case is to allow users to join the system and give them warnings that they are extra joiners and may experience slow response from the system due to load. This can have adverse effect on the system performance but user will be able to work with the system.
Sometimes users may accept slow running system than a system not available.

Here is a simple example that explains spike testing:

Consider a system designed to handle 1000 concurrent users. As soon as one more user tries to enter the system it might give a message that system is already full and nobody can log in at that moment.
Another way of handling is to allow the user to enter the system but system performance may get deteriorated. System might give a message that there could be a performance issue when system overloads.

Hope this article helps you to understand spike testing