What is Stress Testing in Software Testing?

Last Updated : 25 Sep, 2024

Stress Testing is a software testing technique that determines the robustness of software by testing beyond the limits of normal operation. Stress testing is particularly important for critical software but is used for all types of software. Stress testing emphasizes robustness, availability, and error handling under a heavy load rather than what is correct behavior under normal situations.

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What is Stress Testing?

Stress testing is defined as types of software testing that verifies the stability and reliability of the system. This test particularly determines the system's robustness and error handling under the burden of some load conditions. It tests beyond the normal operating point and analyses how the system works under extreme conditions. Stress testing is performed to ensure that the system does not crash under crunch situations. Stress testing is also known as Endurance Testing or Torture Testing .

The process includes assessing the system’s response to heavy loads, identifying weaknesses, and ensuring it remains stable under stress. For a detailed exploration of Stress Testing and its various aspects, including metrics and tools, check out our course, " Complete Guide to Software Testing Metrics ," at GeeksforGeeks.

Prerequisite - Types of Software Testing

Key takeaways of Stress testing

Stress testing is a technique to see how banks and investment portfolios handle extreme economic situations.
It helps measure investment risk, check if assets are adequate, and evaluate internal processes and controls.
Stress tests can use historical data, hypothetical situations, or simulated scenarios.
Regulations require banks to conduct various stress tests and report on how they manage capital and risk.
The Federal Reserve mandates that banks with $100 billion or more in assets must perform stress tests.

Characteristics of Stress Testing

Identification of Risk: Stress testing's main objective is to locate and evaluate a system's possible hazards and weaknesses.
Quantitative and Qualitative Analysis: While numerical data are crucial, it's also critical to comprehend the qualitative characteristics of the system's response and potential weak points.
Variable Parameters: Stress testing includes changing variables including interest rates, market conditions, transaction volumes and outside influences that could have an impact on the system.
Cross-Functional Involvement: Many departments within an organization must work together and participate in stress testing. This cross-functional strategy makes sure that the stress testing procedure benefits from a variety of viewpoints and specialties.
Open and Honest Communication: Stress testing necessitates open and honest communication regarding the goal, approach, and outcomes of the testing procedure.

Need for Stress Testing

To accommodate the sudden surges in traffic: It is important to perform stress testing to accommodate abnormal traffic spikes. For example, when there is a sale announcement on the e-commerce website there is a sudden increase in traffic. Failure to accommodate such needs may lead to a loss of revenue and reputation.
Display error messages in stress conditions: Stress testing is important to check whether the system is capable to display appropriate error messages when the system is under stress conditions.
The system works under abnormal conditions: Stress testing checks whether the system can continue to function in abnormal conditions.
Prepared for stress conditions: Stress testing helps to make sure there are sufficient contingency plans in case of sudden failure due to stress conditions. It is better to be prepared for extreme conditions by executing stress testing.

Purpose of Stress Testing

Analyze the behavior of the application after failure: The purpose of stress testing is to analyze the behavior of the application after failure and the software should display the appropriate error messages while it is under extreme conditions.
System recovers after failure: Stress testing aims to make sure that there are plans for recovering the system to the working state so that the system recovers after failure.
Uncover Hardware issues: Stress testing helps to uncover hardware issues and data corruption issues.
Uncover Security Weakness: Stress testing helps to uncover the security vulnerabilities that may enter into the system during the constant peak load and compromise the system.
Ensures data integrity: Stress testing helps to determine the application's data integrity throughout the extreme load, which means that the data should be in a dependable state even after a failure.

Stress Testing Process

The stress testing process is divided into 5 steps:

1. Planning the stress test

This step involves gathering the system data, analyzing the system, and defining the stress test goals.

Gathering System Data : For a web application, collect details about server specifications, database configurations, network bandwidth, and current traffic patterns.
Analyzing the System : Evaluate how the web application performs during peak traffic times, such as during a sales event. Identify any existing issues like slow page loads or database timeouts.
Defining Stress Test Goals : Set goals such as ensuring the application can handle a traffic spike of 10,000 users per minute without crashing and maintaining response times below 2 seconds.

2. Create Automation Scripts

This step involves creating the stress testing automation scripts and generating the test data for the stress test scenarios.

Developing Stress Testing Scripts : Use tools like Apache JMeter or LoadRunner to create scripts that simulate user actions such as logging in, browsing products, and making purchases.
Generating Test Data : Create datasets that include various user profiles, product inventories, and transaction records to ensure the test is realistic and comprehensive.

3. Script Execution

This step involves running the stress test automation scripts and storing the stress test results.

Analyzing Test Data : Review the logs to identify performance trends. Look for any significant slowdowns or failures as the load increases.
Identifying Bottlenecks : If the application slows down significantly at 5,000 users, investigate the server logs to determine if the issue is related to database queries, server CPU limits, or network bandwidth.

4. Result Analysis

This phase involves analyzing stress test results and identifying the bottlenecks.

Running the Stress Test Scripts : Execute the scripts in a test environment that mirrors the production setup. Gradually increase the number of simulated users to observe how the system handles the load.
Storing Test Results : Use logging tools to capture performance data such as server response times, error rates, and resource utilization metrics.

5. Tweaking and Optimization

This step involves fine-tuning the system and optimizing the code with the goal meet the desired benchmarks.

Fine-Tuning the System : Based on the findings, optimize database queries, increase server CPU capacity, or enhance network configurations.
Optimizing for Desired Benchmarks : Retest the application to ensure it now handles 10,000 users per minute with response times below 2 seconds.

Types of Stress Testing

Here are the following Types of Stress Testing

1. Server-client Stress Testing

Server-client stress testing also known as distributed stress testing is carried out across all clients from the server.

Also known as Distributed Stress Testing , this type involves testing the performance and robustness of a server by simulating multiple clients. The aim is to assess how well the server can handle numerous simultaneous requests from different clients.

Example : Imagine a web application where thousands of users try to log in simultaneously. The server-client stress test would simulate these concurrent logins to ensure the server doesn't crash and can handle the load effectively.

2. Product Stress Testing

Product stress testing concentrates on discovering defects related to data locking and blocking, network issues, and performance congestion in a software product.

Product Stress Testing focuses on identifying issues related to data locking, network problems, and performance bottlenecks within a specific software product.

Example : In a database application, product stress testing might involve simulating multiple transactions occurring simultaneously to check for issues like data locks or network slowdowns, ensuring the system can handle real-world usage without significant delays or crashes.

3. Transactional Stress Testing

Transaction stress testing is performed on one or more transactions between two or more applications. It is carried out for fine-tuning and optimizing the system.

Transactional Stress Testing is performed on transactions between two or more applications. This type of testing aims to optimize and fine-tune the system by simulating high volumes of transaction loads.

Example : For an e-commerce platform, transactional stress testing could simulate thousands of transactions per minute between the payment gateway and the order management system to ensure the process remains smooth and error-free under peak loads.

4. Systematic Stress Testing

Systematic stress testing is integrated testing that is used to perform tests across multiple systems running on the same server. It is used to discover defects where one application data blocks another application.

Systematic Stress Testing involves integrated testing across multiple systems running on the same server. This approach helps identify defects where one application's data processing might interfere with another application on the same server.

Example : On a shared server hosting multiple applications, systematic stress testing might reveal that a heavy load on a database application slows down a concurrent web application, highlighting the need for resource optimization or separation.

5. Analytical Stress Testing

Analytical or exploratory stress testing is performed to test the system with abnormal parameters or conditions that are unlikely to happen in a real scenario. It is carried out to find defects in unusual scenarios like a large number of users logged at the same time or a database going offline when it is accessed from a website.

Example : Analytical stress testing might involve simulating scenarios where the database goes offline while thousands of users are accessing the application, or where the application faces a sudden surge in traffic due to a viral event. This helps identify vulnerabilities that might not be apparent under normal conditions.

Advantages of Stress Testing

Determines the behavior of the system: Stress testing determines the behavior of the system after failure and ensures that the system recovers quickly.
Ensure failure does not cause security issues: Stress testing ensures that system failure doesn't cause security issues.
Makes system function in every situation: Stress testing makes the system work in normal as well as abnormal conditions in an appropriate way.
Improving Decision Making: Decision-making processes can benefit from the insightful information that stress testing offers.
Increasing Stakeholder confidence: Providing clear information about the outcomes of stress tests helps boost stakeholder confidence. Organizations that show a proactive approach to risk management are valued by investors, customers, and other stakeholders, since it cultivates credibility and confidence.

Disadvantages of Stress Testing

Manual stress testing is complicated: The manual process of stress testing takes a longer time to complete and it is a complicated process.
Good scripting knowledge required: Good scripting knowledge for implementing the script test cases for the particular tool is required.
Need for external resources: There is a need for external resources to implement stress testing. It leads to an extra amount of resources and time.
Constantly licensed tool: In the case of a licensed stress testing tool, it charges more than the average amount of cost.
Additional tool required in case of open-source stress testing tool: In the case of some open-source tools, there is a need for a load testing tool additionally for setting up the stress testing environment.
Improper test script implementation results in wastage: If proper stress scripts or test cases are not implemented then there will be a chance of failure of some resources and wastage of time.

Stress Testing Tools

Jmeter : Apache JMeter is a stress testing tool is an open-source, pure Java-based software that is used to stress test websites. It is an Apache project and can be used for load testing for analyzing and measuring the performance of a variety of services.
LoadNinja: LoadNinja is a stress testing tool developed by SmartBear that enables users to develop codeless load tests, substitutes load emulators with actual browsers, and helps to achieve high speed and efficiency with browser-based metrics.
WebLoad: WebLoad is a stress testing tool that combines performance, stability, and integrity as a single process for the verification of mobile and web applications.
Neoload: Neoload is a powerful performance testing tool that simulates large numbers of users and analyzes the server's behavior. It is designed for both mobile and web applications. Neoload supports API testing and integrates with different CI/ CD applications.
SmartMeter: SmartMeter is a user-friendly tool that helps to create simple tests without coding. It has a graphical user interface and has no necessary plugins. This tool automatically generates advanced test reports with complete and detailed test results.

Metrics of Stress Testing

Metrics are used to evaluate the performance of the stress and it is usually carried out at the end of the stress scripts or tests. Some of the metrics are given below.

Pages Per Second: Number of pages requested per second and number of pages loaded per second.
Pages Retrieved: Average time is taken to retrieve all information from a particular page.
Byte Retrieved: Average time is taken to retrieve the first byte of information from the page.
Transaction Response Time: Average time is taken to load or perform transactions between the applications.
Transactions per Second: It takes count of the number of transactions loaded per second successfully and it also counts the number of failures that occurred.
Failure of Connection: It takes count of the number of times that the client faced connection failure in their system.
Failure of System Attempts: It takes count of the number of failed attempts in the system.
Rounds: It takes count of the number of test or script conditions executed by the clients successfully and it keeps track of the number of rounds failed.

Conclusion

In conclusion, stress testing is a critical software testing technique that evaluates a system's robustness and reliability under extreme conditions beyond normal operations. It ensures applications can handle heavy loads, recover from failures, and maintain security and data integrity. By identifying weaknesses and optimizing performance, stress testing enhances decision-making, builds stakeholder confidence, and mitigates risks associated with system failures.