Stress Testing

What is Stress Testing ?

Nowadays, software and applications are designed and developed to be used by multifarious users simultaneously, which has made testing these software systems and applications, through various performance testing techniques necessary. Stress testing, which is a type of performance testing, is executed by the team to ensure the product’s performance and functionality under varying load and stress. Hence, to help you reap various advantages of stress testing, defined below are its various components.

Why Stress Testing is Needed?

Stress testing is an important software testing technique, performed by the team of software testers to determine the robustness of the mission critical software product. This type of performance testing prevents system failures and ensures that the software is able to bear the maximum possible load under extreme conditions.

Stress testing focuses on breaking the system/software product, to determine its maximum or threshold limit, to bear the loads under unexpected or abnormal conditions, before being crashed out.

In addition, it is also done with the purpose of evaluating the recoverability power of the system, after its failure, so that the system recovers without any issues, like loss of data.

Characteristics of Stress Testing:

Considered to be an amalgamation of quantitative and qualitative tests, stress testing, helps ensure the stability and reliability of the software product. It emphasizes the robustness of the software as well as its error handling capabilities. Other characteristics of stress testing are:

  • A form of both performance and non-functional testing.
  • It mainly focuses on recoverability aspect of the software or system, to ensure its hassle-free recovery, after the failure.
  • Evaluates, software's robustness to go along with the maximum possible load under unfavourable conditions.
  • Determines the breaking limit or point of the system, just before its failure.
  • It tests the system’s behaviour under normal and abnormal scenarios.
  • Determines the breaking point of the system, just before its failure.
  • When the system fails, stress testing ensures that there is no loss or corruption of data.
  • Very often, stress testing is addressed as negative testing.
  • Ensures software's error handling and managing feature, responsiveness and throughput evaluation, under heavy load.
  • It is different from load testing. The purpose behind load testing is to assess the system's behaviour and response under different load whereas stress testing is a brutal version of load testing, which includes excessive burdening the system, along with other negative approaches such as multiple and simultaneous access, limiting the resources, space and memory, etc., in order to break it.

Why is Stress Testing Needed?

To determine the number of users who will be concurrently accessing or using a software product or system, is difficult. For example, the traffic on the e-commerce websites is at its peak during the festive season. The failure of any e-commerce website to accommodate this heavy traffic, offers an advantage to its competing websites, along with the loss of its revenue and market value. In such instances, stress testing comes to the rescue of the organization in the following ways:

  • Ensures the capability of software products to withstand the unforeseen traffic or load under severe circumstances, without having gone into a failed state, along with successful recovery, in case of failure.
  • Allows the team to monitor the performance of the software system during failures.
  • Makes sure that unexpected system failures do not cause security issues, like the breach of privacy policy, data, etc.
  • Verifies whether the system delivers relevant error messages during system failure or crash.
  • Ensures that the data is saved before the system’s failure after a period of time.

Types of Stress Testing:

There are five types of stress testing, which test different aspects of a software or an application. These stress testing types ensure that the software does not crash due to insufficient resources by emphasizing the availability and error handling under heavy loads. The various types of stress testing are:

  1. Distributed Stress Testing: During this type of stress testing, the tests are executed across all clients from the server to track their status as well as to identify failures due to excessive stress.
  2. Application Stress Testing: The focus of this testing is on finding defects in the software that are related to data locking and blocking, network issues, and performance bottlenecks.
  3. Transactional Stress Testing:Transactional testing does stress testing on one or more transactions between various software products or applications. Its main aim is to fine-tune and to optimize the system to improve its performance.
  4. Systematic Stress Testing: An integrated stress testing, systematic stress testing, is used to test multiple systems running on the same server. It enables the testing team to detect defects where data of one software blocks another software.
  5. Exploratory Stress Testing: It is used to test the system with unusual conditions that are unlikely to occur in a real scenario. These stress tested scenarios allow the team to detect various undetected issues and bugs in the system.

Process of Stress Testing:

During stress testing, testers measure various aspects of the software, by putting it under different user load. This allows them to measure the frequency of the system crashes and the software’s ability to resist denial of service (DOS) attacks. However, to ensure the accuracy of the test results and the system’s performance, it is crucial for the team to implement the correct testing methodology. Therefore, here is the process of stress testing:

  • Identify Test Objectives: The testing team defines the objective of stress testing and prepare an execution plan accordingly. Moreover, they also prepare resources, like tools, testers, etc.
  • Establishing Important Scenarios: Here, the team establishes the key scenarios for stress testing that play a major role in the success of the product.
  • Workload Identification: Another important stage of the process, here, the team defines the workload that will be applied to the software to test its threshold limit.
  • Design Test Cases: During this stage of the process, the team designs and creates test cases based on the testing requirements.
  • Load Creating: After the completion of earlier stages, the load is simulated on the software to test its performance under unpredictable load.
  • Result Analysis: Finally, the captured test data is analyzed and compared against the accepted level of metrics, defined by the team earlier.

Actions Involved in Stress Testing:

This type of testing generally involves a strategy of continually burdening the system or software product with the load, under rigorous environment. This strategy may include:

  • Simultaneous access to software product by a large number of users.
  • Cutting down of the resources, such as memory and space.
  • Execution of tasks by multiple users in a limited or short time.
  • Performing critical operations at the same time by the users.
  • Attempting to hack the system and using it to spread spam.
  • Running several resource-intensive software and applications in the system to test its performance.
  • Concurrently attempting to access a single application, website, or software.

Ensure the accuracy of your stress testing with our stress testing checklist.

Advantages of Stress Testing:

Stress testing is among the most beneficial software testing techniques, which allows the team to ensure the performance of the software. Moreover, it validates the security, reliability, and error handling abilities of the software, which further improves its quality. Other advantages offered by this testing are:

  • Offers assistance in determining the stability of the software system beyond its normal operational capacity.
  • Makes the software crashproof in scenarios where the computational resources are scarce.
  • Simplifies the process of testing an application’s concurrency.
  • Helps to find deadlocks in the software product.
  • Ensures the performance of the software under various load conditions.

Tools Used for Stress Testing:

There are numerous tools available in the market for carrying out stress testing. Some of them are:

Difference Between Load and Stress Testing:

Stress testing and load testing are though types of performance testing, they are focused on testing and ensuring different aspects and components of the software. Therefore, to signify the difference between these two types of performance tests here is a detailed comparison of load and stress testing.

Load Testing Stress Testing
1. The aim of load testing is to ensure the reliability of the software product 1. The aim of stress testing is to ensure the stability of the software.
2. It allows the team to test the performance and behavior of the product under various load. 2. It helps the team to identify the breaking point of the software under extreme load.
3. Helps to recognize the upper limit of the software and to check how it handles the heavy load. 3. Allows the team to check how the system behaves under extreme load and stress.
4. Determines the operating capacity of the software product. 4. Checks whether an unexpected failure does not impact the security of the software.

Find out more differences between these two types of performance tests in our next article, volume testing vs load test vs stress testing.


Stress testing is an integral part of the software testing life cycle (STLC) and is used by the team to ensure the performance of the software and to establish its security and reliability. Moreover, it helps to create a product that can withstand any use load without any difficulty or crashes.