Load testing is a part of performance testing (non-functional testing type), which includes an effective process of subjecting applications, websites, servers, networks, or systems to varying loads per their specification limits to check the stability of the app, server, network, or system. This testing method includes simulating a real-world load on any app or website to check how it responds to heavy user loads in real-time. Load testing checks whether the app or website meets the performance goals and objectives. Further, this testing method also determines the system behavior under normal conditions and anticipated or expected peak load conditions.
What is the Importance of Load Testing?
The most critical part of web and mobile applications lies in their ability to deliver seamless performance to the end users. Undoubtedly, poor performance is bound to affect the customer experience as users prefer applications that provide great performance and are easy to use. Hence, to achieve seamless and high-performing apps, Load testing should be performed to evaluate the system’s response time and performance under varying loads. Businesses should adopt load testing as a part of their software development life cycle (SDLC) under both Agile and DevOps processes to get high-performing, scalable and robust apps.
Advantages and Disadvantages of Load Testing
Advantages of load testing
• Helps to improve the scalability of apps and reduces downtime risk.
• Helps to improve website traffic in case of holiday sales.
• Helps to identify performance bottlenecks before deployment.
• Discovers the performance of database components.
• Verifies if the application meets the desired performance objectives.
• Helps to uphold the reliability of the system.
• Improves customer experience with scalable and robust systems in place.
Disadvantages of Load testing
• Many of the load testing tools are licensed and needed to be paid to get the license
• Some of the load-testing tools support only web applications
• Some of these load-testing tools have limited compatibility
• Some load tools might be challenging to test complex applications
Goals of Load testing
• To check how the website, app, or system performance under load conditions
• Identify performance issues within the system for scalability, reliability, and stability under load conditions
• Check the overall performance issues of critical business transactions, user flows, resource utilization, etc.
List types of load testing
This testing type, also called scalability testing, is used to identify the maximum number of users the system can support while not exceeding the page time as defined. The scalability testing method measures how far the system is scalable by adding resources. This testing method also measures the ability of the app to scale up or down when there is an increase in the number of users.
This testing type helps to find out how a system behaves under extreme conditions such as breaking of the system, doubling the users, a database with less memory, etc.
This testing type is used to know the trends and changes in the system behavior during a long duration of time.
This testing method is used to check how the system can cope with sudden traffic spikes due to a sudden burst of traffic or heavy loads.
Best Practices of Load Testing
Identify business objectives for test preparation:
During the test preparation, the first important need is to identify the business objectives. This helps to recognize the type of tests to be performed, such as pre-production performance, stress, and capacity tests. Secondly, the requirement is to understand the use cases, such as considering the type of user requests, estimating the number of users to run the test, and identifying the behavior during load tests. The next phase is planning the test infrastructure, followed by deploying and tuning the test infrastructure.
Validate real-time performance with KPIs:
One of the best practices is to establish KPIs to measure the real-time performance of the application, such as the storage, response time, usage of the resources, etc.
Choose an effective Load testing tool:
Understanding the application technology stack plays an important role in choosing the right load testing tool. Several open-source and commercial load testing tools are available, but opting for the right tool can help achieve business goals.
Create load test cases based on user scenarios:
Effective load tests are the ones that simulate real-time traffic on the application instead of placing an unrealistic load on the system.
Build a replica of the production environment:
Concluding the load test results is difficult for businesses. If the test cases are run in a production-like environment (in terms of capacity and configuration), it can result in high business risk. Hence, businesses must replicate the production environment to avoid such scenarios.
Run Load tests to avoid bottlenecks:
It is a best practice to perform the load tests with a few users while preparing for the load test. Later, the number of users should be increased steadily. This way of running load tests will help to resolve the fluctuations once the user load increases.
How does Load Testing work?
The QA teams need to follow the below steps to perform load testing:
• Define key objectives and user scenarios
• Identify the workload
• Identify business SLAs
• Choose the correct load test tool
• Create test scripts
• Create load test scenarios
• Prepare the required test data
• Run the load test
• Record user transactions
How to do website load testing?
• Understand the requirements
• Determine which load test to perform
• Identify the peak number of concurrent users expected to be handled by an app
• Determine the usage model for the app and replicate the same while devising a load-test scenario
• Develop automated scripts simulating user journeys for the identified business scenarios
• Do not include third-party sites and CDN assets
• Group different web pages into transactions
• Execute the load tests
• Monitor the web, applications, and database servers
• Analyze the results and data
• Share result analysis report along with actionable recommendations
• Collaborate with developers and help them replicate the performance issues
• Retest and assert the performance fixes once developers have implemented the tuning recommendations
Some Use Cases of Load testing
• eCommerce websites during Black Friday sales