December 3, 2020

Why Load Testing is Important

Performance Testing

As a developer or QA engineer, you probably incorporate many types of tests into your code checking: unit tests, integration tests, UI tests, and more. Occasionally, load tests might be overlooked in a sprint or release process. After all, if the system is working under functional testing, it’s good to go, right? Wrong.


[What is load testing? Click here to read more.]


Table of Contents:


Here are seven reasons you should load test every time you commit.


1. Load testing simulates real user scenarios


When testing your website, app, or API endpoint under a load, you are actually simulating how it will perform when hundreds, thousands or millions of users visit it in real life. Don’t neglect the real people who will use your system or product. Understand, analyze, and fix errors, bugs, and bottlenecks before they actually happen. Your system may, depending on the limits of its resources, perform completely differently for one user (functional testing) compared to many (load testing) -- which leads to our next point.


2. Your system performs differently under a load


KPIs like response time, error rate, memory leakage, and CPU consumption might be top-notch when running functional tests, but when scaling to thousands of users from all over the globe, they could suddenly plummet and require dev attention. Load test to learn where and when your system breaks, fix the problems, and avoid upset users and revenue loss. 

Incorporate different types of load when you’re load testing. For example, test for sudden spikes, test maintaining a super-heavy load over time, and test gradually increasing the load to a forecasted real-life volume. Such tests will help you learn how your system reacts to different traffic events.


3. Your code can change your product in unexpected ways


Let’s assume you’re a responsible developer who actually tested your system two months ago. The results showed that most of the API endpoints and services worked. Some small bottlenecks were detected, but you fixed them, ran the test again, and saw that everything was performing well. You know you’ve made some code changes since then; in fact, you’ve likely released new versions.

These modifications may have affected your system in unexpected ways, perhaps due to dependencies, heisenbugs, or other reasons not yet readily apparent. Your system’s ability to handle a heavier load may have likewise been affected. To ensure you’re not surprised by a crash or slow responsiveness, run an automated load test as part of your continuous integration cycle, every time you commit.


4. You can't be fully agile without it


Faster releases, lighter versions, and more automation create a better product and make for a better working environment for developers and engineers. Load testing with every commit is an inherent part of any continuous integration process, alongside issue management, code analysis and other lifecycle activities. 

When you’re setting up your automated continuous integration cycle with open-source tools (such as Jenkins), add load testing to your workflow. Include open-source load testing tools (such as Apache JMeter™), and if you need to test in the cloud in order to simulate users from across the globe, run your load tests with BlazeMeter.


5. Users are impatient and unforgiving


Every time an important website crashes, headlines announce the blunder and angry users take to social media and condemn the website's owners for not taking proper measures to avoid the crash. Unsatisfied customers have a good memory and there is a limit to the number of times they will try to revisit a slow or unreliable website. Instead of desperately trying to get your website up while under pressure, dealing with frantic PR managers, and investing money in re-branding, just load test on time.


6. Load testing saves you money


Teaching developers to set up and automate load tests will take up some resources, but it will cost more to constantly fix website crashes and restore your brand reputation after scores of unhappy customers are fed up and move on to your competitors. For example, one minute of downtime on Black Friday costs $4,700 on average. 

Now consider the reverse: If your competitor’s site crashes while yours remains stable (because you load tested beforehand), you can seize the opportunity and win their users over, increasing your revenues.


7. Big events like Black Friday are too important to disregard


Think about major events like Black Friday and Cyber Monday, big sports days, music festivals, flash sales, all the many other exciting days that ignite a massive crowd’s interest. Those events result in enormous traffic spikes and thus require special load testing beforehand, above and beyond your regular load testing. 

First, you need to understand how your system will react to such irregular traffic patterns.

Second, your massive audience deserves reliable service. That crowd can bring in very high revenue, so do everything you can to ensure a smooth experience.


Load Testing with BlazeMeter


Use SaaS-based BlazeMeter to easily scale and run your load tests. Just upload your test file, optionally configure it to your liking, then run it. You’ll see real-time results while it runs, displayed via insightful graphs. You can record data for multiple test runs over time so that you can identify and analyze various trends. BlazeMeter even integrates with CI tools like Jenkins, TeamCity and Bamboo.

Image of test

This blog was updated November 2020 for accuracy.