Soak testing is a non-functional performance testing under which an application is exposed to a continuous load for a pre-determined period. It is also known as Longevity testing and Endurance testing.
The term 'soak' itself explained the test's purpose. Let's consider yourself pulling a rope on one end while your friend pulls it on the other end. Now, if you pull it for one hour, it won't affect the rope much. However, if both of you continue to pull it for days, the rope might eventually break.
The same rules apply to software as well. When software faces a high load, it may work fine for a couple of hours. However, if it continues for 15-20 hours, the software may collapse at some point.
This is where Soak testing can help developers to understand the load endurance capability of the software. In soak testing, an application is loaded with specific users for a particular timeframe. This allows developers to identify the various underlying issues which might go unnoticed.
Although it is recommended to run the soak test as long as possible, it largely depends on the system quality you choose to run the test.
Below are the examples when soak testing is primarily recommended during −
Heavy transactions − Soak testing is ideal for websites or applications facing huge transaction rates, let's say 1000 transactions in an hour.
Non-stop operation − Software may collapse when you conduct a lot of tasks in a limited time. It is most noticeable when employees try to finish off their pending work on Monday after a weekend break. In other words, you try to complete days' worth of work in one day.
Rare announcements − If an ecommerce website announces heavy discounts for a specific time for a couple of days, then many transactions can be expected during these days. Situations like these are rare, but you must be sure your system can handle them.
A soak testing helps validate the efficiency of software and system based on how it performs during heavy load.
Soak testing helps in early detection of −
Response time degradation – Heavy loads can negatively affect a software/system by increasing its response time, causing a significant setback in user experience. With soak testing, developers can detect response time degradation and fix it at its earliest.
Memory leaks – Memory leaks can reduce the amount of available memory, thereby reducing the overall performance of the system. In the worst case, it can make the device/system stop working, crash the application, or slow it down. Soak testing allows developers to find out any possible memory leaks and create strategies to fix them.
Database Connections Failure – Incorrect database information, corrupt database, or irresponsive database server can lead to database connection failure. Meaning, the system/device fails to connect with the database to retrieve the requested information. Heavy load sometimes can cause databases and systems to crash. Therefore, soak testing is necessary to detect these issues beforehand.
Network Layer Connections Failure – The network layer helps in transferring network packets from the source to destination via various networks. Overloaded/underloaded servers, traffic congestion, unsuitable router configurations, and chronic frame loss can form bottlenecks, causing network layer connection failure. Soak layers enable developers to detect such connection failures and act proactively to resolve the issues.
Before running a soak testing, testers need to prepare a four-step strategy −
Creating a test environment – The team must work together in deciding the appropriate hardware, software, OS, and database for running the test.
Developing test scenarios – The testing team must work together in designing, assessing, and finalizing different test scenarios. Testers choose appropriate functionality tests by considering real-life scenarios and test cases.
Finalize test estimation – In this stage, the testing team sets the duration of the soak test by considering essential factors like the number of expected users, system configuration, server capacity, etc.
Analyze risks – Testers evaluate the risk associated with running a soak testing. All risks and issues are noted down, discussed, and a proper mitigation plan is prepared for the same.
Like all performance testing, soak testing also comes with several challenges.
Time-consuming process – Soak testing must be executed by having an extended timeframe at hand. It is not a test that can be conducted within a couple of hours. In most cases, it can take up to more than one day.
Requires both tools and expertise – Both automation tools and technical expertise are mandatory for running a successful soak test. The test consumes a significant amount of data and time. On top of that, you need the analytical and technical skills of testing experts as well.
Difficult to determine the test volume – It's difficult to determine how much test is needed to be done. The whole test is done by considering past test cases and scenarios. This is where you need the help of an expert tester team.
Can be risky – Testers must detach the test environment from the live production environment. Any errors discovered during the test may lead to permanent data loss or corruption.
Soak testing is a part of performance tests that are primarily conducted along with several other testing procedures. We hope you have understood the role of soak testing in software testing and the issues it addresses. In this day and age, where a moment delay leads to the loss of millions, one can easily infer the importance of performance testing procedures like soak testing.
Soak testing helps in the early detection of software/system failure caused by a heavy load. The objectives behind running a soak testing are to −
Evaluate software behavior when exposed to heavy loads for a prolonged period
Understand the performance level of the system
Make sure the system is adequate for heavy load
Predict system failure
Tools that are mainly load testing can also be used for soak testing. Some automated soak testing tools include LoadUI, Appvance IQ, Apache JMeter, and WebLOAD, etc. Besides, you can also use Jenkins and GitHub for soak testing by adding some special plugins.
Developers most conduct soak tests after the load testing. After installing the build, the testing should be done by executing it through a series of high traffic load tests.
Soak testing is a time-consuming task as it can go on for days. Hence, it's better to conduct the test during the weekend when no other tests are active.