Using software involves the simultaneous operation of many users, and in such situations there is a need for performance testing under load (under stress).

Stress testing is a kind of testing of an application or server in the conditions of exceeding the limits of normal operation.

Stress testing is aimed to determine system performance and predict system behavior under stressful conditions.

This type of testing is also used to assess the ability of the system to return to normal after reducing the voltage to a normal level.
Stress testing is especially important for mission-critical software.

Goals for stress testing:

• General study of the behavior of the system under extreme loads
• Examination of handling errors and exceptions under extreme loads
• System bandwidth testing
• Study of some parts of the system or its components under conditions of disproportionate load

Performance testing

Performance testing and load testing should be conducted early in the design and software life cycle in order to meet performance requirements and configure test design, as well as development efforts.
Performance errors that are not noticed and not eliminated before launch can lead to costly improvements and a hard start.

When conducting performance testing, we get information on how to follow performance requirements in terms of applications, network, servers, and how to perform load, volume, and stress testing, etc.

As performance testing includes load testing, stress testing and scalability testing, reliability testing and volume testing.
For example, some load tests check the required load level by increasing the number of virtual users in order to achieve a certain level of performance.

Stress testing is performed by increasing the duration of load cycles and the number of unsuccessful attempts, and, at the same time, by reducing the response time.
During the scalability check, we are testing the application for an increasing number of concurrent users to determine when the application is failing. The objectives of scalability testing depend on the business needs and the criticality of the application under test.
By applying these various types of testing, our approach to performance testing allows us to make the application more reliable by identifying where, when and under what circumstances the application fails.

Reliability testing

Reliability testing determines how long an application can maintain optimal performance.

The purpose of reliability testing (also called stability testing) is to test the system’s performance during multi-hour testing with an average load level.

Reliability testing provides the data needed to monitor and control technical parameters that can help increase product life.

The main task of stability testing is to identify memory leaks, server restarts under load, or other problems that prevent the system from working stably.

Volume testing

The purpose of volume testing is to evaluate the performance of the system with increasing data volume.
This is a very important type of testing, with which we can determine whether a system or application can process large amounts of data without errors.

As part of the volume of testing the following activities are performed:

• Fixing the time required to perform certain actions at a set intensity of these actions
• Determining the number of users working with the application at the same time