Stress Testing In Software Testing: With Best Practices

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Stress testing is a type of performance testing in which a system is subjected to a workload beyond the limits of its normal operations to determine how it behaves under such scenarios. The primary objective of stress testing is to identify bottlenecks, evaluate system response times, and detect any flaws or failures when the system is under stress.

With the demand for products and services going off the roof, software services experience insanely high amounts of stress at unexpected times. It calls for a method that ensures optimal performance regardless of the stress.

Using stress tests, you can identify potential issues that can pop up when the system is used in real-user conditions and enable developers to tweak the system to ensure it can handle the intended load.

What is Stress Testing?

Stress testing, also known as load testing or endurance testing, is a method of testing the performance and stability of a system, device, or component under extreme or abnormal conditions.

The goal of stress tests is to identify any weaknesses or vulnerabilities in the system that may cause it to fail or perform poorly under high-stress levels or unexpected circumstances.

Stress testing applies to various systems and components, including servers, networks, databases, websites, and software applications. It ensures that a system can handle the expected load or traffic in real-world conditions and test its ability to recover from failures or unexpected events. Overall, stress tests are essential for ensuring efficient and hassle-free working of systems in various industries, from IT and web development to finance and healthcare.

In today's world, systems and devices receive a massive push to their limits more and more, with increasing user demands and the growing dependency on technology in almost every aspect of our lives. Stress tests also validate the performance and reliability of specific components or systems within a more extensive system, such as a database or server.

Why Stress Testing?

Stress testing helps you identify potential issues and weaknesses in a system before it is deployed in the live environment.

By mimicking real-world environments, developers and testers can check how the system will perform under heavy loads or stress and make any necessary tweaks or improvements to improve the system's performance.

There are several reasons why stress tests are essential.

  • Identify weaknesses and vulnerabilities: Stress testing helps organizations identify weaknesses or vulnerabilities in their systems that may cause them to fail or perform poorly under high-stress levels. Organizations can avoid costly downtime or other disruptions caused by system failures by identifying and addressing these issues early on.
  • Ensure system reliability: Reliability is a crucial concern for any organization, and stress tests help ensure that systems can handle the demands placed on them in real-world conditions. This is especially important for systems critical to a business's operation, such as servers, databases, and networks.
  • Meet customer expectations: In today's world, users expect systems to be available and perform at a high level all the time. Stress tests help organizations meet these expectations by ensuring their systems can handle the demands users place on them.
  • Avoid costly disruptions: System failures can be expensive, not just in terms of lost revenue but also in terms of the time and resources needed to fix the problem. Stress tests help organizations avoid costly disruptions by identifying and addressing potential issues before they become serious.

Real-World Examples of Stress Testing

Here are some real-world examples of stress tests.

  • During mega sales, eCommerce websites would see a significant increase in traffic.
  • When university websites publish exam results, multiple users will check the results simultaneously.
  • News or an important event that boosts traffic to news websites or blogs.
  • When the stock market fluctuates, finance-related applications or websites surge in traffic.

Benefits of Stress Testing

In addition to identifying the system’s weaknesses and improving resiliency, running stress tests provides several benefits. The following are the ones.

  • It can identify areas of a system that might not be able to handle extreme conditions, such as high traffic or a downturn in the market. This might result in system failures.
  • The objective of a stress test is to identify and address system weaknesses to improve the overall resiliency of a system, making the system more capable of coping with unexpected events.
  • As compared to fixing real-world issues, this can be a more cost-effective method for identifying system weaknesses and addressing them.
  • It helps organizations prioritize systems and processes that require immediate attention and plan accordingly with available resources.
  • It ensures that the system recovers quickly from crashes during times of failure.

Load Testing vs. Stress Testing

Load testing mimics normal or anticipated utilization, whereas stress tests simulate extreme conditions beyond normal operating parameters. Let’s look at how both testing types differ.

Load TestingStress Testing
Identify the extreme limit of the system to check how it handles heavy loads.Identify how the system copes with extreme loads and recovers from failure.
Executed to test the system's performance under heavy load.Executed to test the system's robustness under heavy load.
It checks for attributes like server throughput, response time under different load levels, peak performance, etc.It checks for attributes like bandwidth capacity, stability response time, etc.
Determine bottlenecks and also help testers to analyze the root cause.Help testers by determining memory leaks, security issues, etc.
In this type of testing, the large chunks of users represent the test data.In this type of testing, many users and data represent the test data.

Types of Stress Testing

Several different types of stress tests evaluate the performance and stability of a system, device, or component. Some of the most common types of stress tests include.

  • Load testing: It involves subjecting a system to high levels of traffic or requests to test its performance and stability. This testing ensures that a system can handle the expected load or traffic in real-world conditions.
  • Volume testing: It involves testing a system's ability to process large volumes of data. This type of testing is often used to ensure that a system can handle the data demands it will encounter in real-world conditions.
  • Application testing: This testing can help organizations identify software defects and application performance bottlenecks.
  • Transactional testing: It can be used to evaluate a system's ability to communicate and make transactions between multiple applications.
  • Distributed testing: This type of testing allows developers to test multiple client servers at the same time.
  • Systemic testing: It combines application and distributed testing to identify defects that may block data between applications.
  • Exploratory testing: It involves using abnormal test conditions to understand the potential for unexpected defects in real-world situations.

Cloud-based testing platforms like LambdaTest help you perform exploratory and automation testing across an online browser farm of different real browsers, devices, and operating systems combinations. It also offers a real device cloud and virtual testing platform for your web and mobile application testing needs.

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Overall, the type of stress test most appropriate for a given system will rely on the specific objectives and the characteristics of the system under test. By combining different stress test types, organizations can comprehensively understand how the systems perform and how reliable they are under various conditions.

Stress Test Planning

Effective stress tests require careful planning and preparation. Here are some key steps to follow when planning a stress test.

  • Set goals and objectives: Before planning your stress test, you must clearly understand what you are trying to accomplish. What are you trying to test? What are you trying to learn? What are your goals and objectives for the test? By setting clear goals and objectives, you can focus your testing efforts and ensure you are gathering the information you need.
  • Identify what to test: Once you have established your goals and objectives, you will need to determine what specific systems or components you want to test. This might include particular servers, databases, networks, or software applications. You will also need to decide how to test these systems by simulating real-world traffic or data volumes.
  • Estimate resource requirements: Stress tests can be resource-intensive, so it is important to carefully estimate the resources you will need to conduct the test. This might include things like hardware, software, and personnel. By accurately estimating your resource requirements, you can ensure you have the resources you need to complete the test successfully.
  • Develop a test plan: Once you have identified what you want to test and estimate your resource requirements, you will need to develop a detailed test plan. This should include a description of the test environment, the specific tests you will run, and the criteria for evaluating the test results.

By adhering to these steps, you can ensure that your stress test is well-planned and well-executed, and you can gather the information you need to make your systems withstand stress.

How to perform Stress Testing?

Stress testing takes place in stages. Here are the steps to perform it.

  • Plan the test: The first step in performing a stress test is to plan your test. This should include setting clear goals and objectives for the test, identifying what you want to test, estimating your resource requirements, and developing a detailed test plan.
  • Create automation scripts: Once you have planned your test, you will need to prepare the test environment. This might include configuring hardware and software, installing tools or utilities, and setting up and configuring test scripts or files.
  • Run the test: Once the test environment is set up, you can begin running the test itself. It might involve simulating real-world traffic or data volumes, running multiple demanding applications, or subjecting the system to other types of stress.
  • Monitor tests: While the test is running, it is vital to monitor the system carefully to ensure the performance is as expected. It might include monitoring resource utilization, tracking the performance of critical systems or components, and looking for any signs of failure or instability.
  • Analyze results: Once you have completed the test, it is time to analyze and interpret the results. This should include identifying any issues or failures during the test, evaluating the system's overall performance under stress, and identifying areas for improvement.
  • Tweaking and optimization: This phase involves fine-tuning the system, modifying configurations, and optimizing the code to meet the benchmark.
How to perform Stress Testing

Analyzing test results

Once you have completed your stress test, it is time to analyze and interpret the results. Here are some critical steps to follow when analyzing and interpreting the results of a stress test:

  • Identify any issues or failures: The first step in analyzing the results of a stress test is to identify any issues or failures that occurred during the test. This could include system crashes, errors, or other types of failures.
  • Evaluate the system's performance under stress: In addition to identifying any issues or failures, it is important to evaluate the system's overall performance under stress. This includes measuring response times, analyzing resource utilization, and evaluating the system's stability.
  • Identify areas for improvement: Based on your analysis of the results, you should be able to identify any areas of the system that need improvement. This might include optimizing resources, improving the system's scalability, or fixing any issues or vulnerabilities identified during the test.

Mistakes to avoid in Stress Testing

Stress testing is important for ensuring the reliability and performance of systems, but it is easy to make mistakes that can compromise the accuracy of your test results. Here are some mistakes you need to avoid when conducting stress tests.

  • Testing wrong things: It is important to carefully identify what you want and how you want to test it. Ensure you are testing suitable systems or components and using the appropriate techniques and test tools for your test.
  • Underestimating resource requirements: Stress tests can be resource-intensive, so it is important to estimate your resource requirements carefully. Ensure you have the hardware, software, and personnel to complete your test successfully.

By avoiding these common mistakes, you can ensure that your stress test efforts are practical and provide valuable insights about how your systems can boast enhanced performance and robustness.

Best Practices for Stress Testing

By following these steps, you can thoroughly understand how your system behaves under stress and identify any areas that need improvement. This will help you ensure that your system can handle its demands in real-world conditions and provide a high level of service to your users.

It is essential to follow best practices to get the best outcomes out of all your testing efforts. Here are some best practices to follow when conducting stress tests.

  • Set clear goals and objectives: Before you begin the stress test, it is important to have a clear understanding of what you are trying to accomplish. What are you trying to test? What are you trying to learn? What are your goals and objectives for the test? By setting clear goals and objectives, you can focus your testing efforts and ensure you are gathering the information you need.
  • Use real-world scenarios and data: To get an accurate understanding of how your systems will perform in real-world conditions, it is important to use real-world scenarios and data in your stress tests. This might include simulating realistic traffic patterns or data volumes or using actual customer data in your tests.
  • Properly maintain and update test environments: To get accurate and reliable results from your stress tests, it is crucial to maintain and update your test environments properly. This includes keeping your test systems up to date with the latest software and patches and ensuring that your test data is accurate and up to date.
  • Monitor the test closely: While the test is running, it is essential to monitor the system closely to ensure it performs as expected. This might include monitoring resource utilization, tracking key system components' performance, and looking for any signs of failure or instability.

Metrics used for Stress testing:

Metrics help analyze a system's performance and are used at the end of a stress test. The following are the commonly used metrics.

  • Measuring system scalability and performance
    • Pages per second: It measures the number of pages requested/read per second.
    • Throughput: It measures the volume of data being sent or received.
    • Rounds: It compares the number of times test scenarios are planned with the number of times they are executed.
  • Application response
    • Hit time: An average time to fetch a page or an image.
    • Time to the first byte: Time taken to return the first byte of information (data).
    • Page time: Time taken to fetch the entire information on the page for application under stress test.
  • Failures
    • Failed connections: The number of failed connections refused by the client.
    • Failed rounds: Number of rounds it fails.
    • Failed hits: Number of failed attempts made by the system.


In conclusion, stress tests ensure systems' reliability, robustness, and flawless performance in various industries. By subjecting systems to extreme or abnormal conditions, organizations can identify bottlenecks that may cause the system to fail or crash under high-stress levels. Effective stress tests require careful planning and preparation, and following all the best practices above is essential, leading to a foolproof system.

By incorporating stress tests into their quality assurance processes, organizations can ensure that their systems can handle the demands placed on them and meet the expectations of their users.

Frequently Asked Questions (FAQs)

Why is stress testing needed?

Stress testing is a way to evaluate system performance, stability, and reliability under extreme conditions. It helps identify potential issues and ensure the system is ready for real-world scenarios.

What is stress testing with an example??

Stress testing is a technique to test a system's performance under extreme conditions. For example, a website handling a huge number of users at once might be overloaded by mimicking a sudden increase in traffic. So, it's crucial to run stress tests to evaluate the website's robustness under heavy loads.

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Veethee Dixit

Veethee Dixit is a Computer Science Engineer by degree and a passionate writer by choice. Credit for her profession as a web content writer goes to her knack for writing combined with a technical background. You can also follow her on Twitter.

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Salman Khan

Salman works as a Digital Marketing Manager at LambdaTest. With over four years in the software testing domain, he brings a wealth of experience to his role of reviewing blogs, learning hubs, product updates, and documentation write-ups. Holding a Master's degree (M.Tech) in Computer Science, Salman's expertise extends to various areas including web development, software testing (including automation testing and mobile app testing), CSS, and more.

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