Software Testing Life Cycle (STLC): All You Should Know

Software Testing Life Cycle (STLC): All You Should Know

31 May 2023 • 15 min read

Testing is an integral part of every software development process and post-launch support. Optimizing the testing strategy with approaches like Software Testing Life Cycle (STLC) ensures that a company's product meets expectations and satisfies the audience with a smooth performance.

The numbers demonstrate how critical testing is. According to Ibis World, the revenue of the US software testing industry reached $2.0 billion in 2022.

We at Softermii regularly adopt the Software Testing Life Cycle (STLC) to confirm that your testing process will deliver the expected result. This systematic approach helps us develop high-quality solutions like P2P e-Wallets, communication apps, and other tools that fulfill the client’s requirements and perform great.


So without further ado, let’s discover all the nuances and perks of using STLC in your software development projects!

What is STLC, and what is its role in SDLC?

The Software Testing Life Cycle is part of the Software Development Life Cycle, also known as SDLC. Why a separate name and definition? Because it’s not a one-time process but a sequence of specific testing activities.

During those activities, experts check software to meet specific requirements and ensure it works as expected. If testers spot any bugs or defects, they report them to the development team.

When the software was less complex, testing usually occurred right after the completed development cycle. But the testing process also changed since digital products have become more complicated.

Nowadays, the software testing cycle starts before the product development is complete, continues before its launch, and even afterward (for instance, when adding new features). Still, each STLC phase starts after the SDLC one is over.

Software testing life cycle

Entry and Exit Criteria in STLC

Each phase of the STLC life cycle has its own entry or exit criteria. These criteria guide the testers to meet deadlines and deliver the best results.

Entry Criteria

As the name implies, entry criteria list the requirements a product should meet before the testing starts. In particular, these are communication with the development team, data and test plan examination, a testing environment, access to required documents, and so on.

Exit Criteria

Exit criteria list the requirements and actions a team should complete to end a testing phase. They have to include a high-priority bug description and detailed test cases. Also, they may consider test data, test automation scripts, and more.

Software Testing Life Cycle (STLC) Phases

Each STLC consists of six core phases designed to optimize the testing process:

  1. Requirement Analysis
  2. Test Planning
  3. Test Case Development
  4. Environment Setup
  5. Test Execution
  6. Test Cycle Closure

Software testing life cycle

As you can see, these STLC phases create a convenient structure, streamlining the process for testers. Each stage has its goals and deliverables to provide high-quality outcomes.

Let’s learn more about each of the phases in software testing life cycle.

1. Requirement Analysis

To determine how to conduct testing, experts should understand the expectations from the end product. Therefore, they must obtain and analyze software requirements that the client and the development team set up.

  • Such requirements might refer to the following aspects:
  • Business needs
  • Design and support characteristics
  • System requirements
  • Functional and non-functional specifications and more

The team may turn to brainstorming, prioritization, and blind spot identification during this phase. If the specialists require clarification or additional documents, they may turn to the development team or the client for help.

2. Test Planning

Like every other part of the software development process, testing must be efficient and timely. The Test Planning phase ensures it by setting up the entire process scope ahead.

During this phase, experts estimate the time and effort required. They develop a set of testing types, tools, and environments. Finally, they assign tasks for teams and individuals and assemble this crucial data into a testing strategy.

Next, testers share this strategy with the development team so that everybody is on the same page about the process. It’s especially useful when testing overlaps with the subsequent development stage.

3. Test Case Development

The next of the STLC model phases is the Test Case Development. Throughout this stage, testers utilize the knowledge collected in the previous steps to develop test cases.

This phase is the most flexible one in the entire testing lifecycle. Although the testers should stick to product requirements, they can still choose how to approach testing (which skills to utilize, which tests to run first, and so on).

Nonetheless, each test has to align with the initial requirements. On top of that, the cases should be easy to identify, repeat, and update if necessary.

Before the testers move to the next stage, the team should review and approve test cases for smooth performance.

4. Environment Setup

This phase can proceed with the previous one as the team determines the test environment in the test plan.

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The test environment should represent the following:

  • software and hardware conditions;
  • configurations;
  • frameworks;
  • networks;
  • test data.

The testers also use the devices and tools that the product’s target audience prefers. For example, it may include a browser type and version, the chosen platform (like iOS and Android), the software version, etc.

At this stage, the testing team decides which tools to use. For instance, JIRA helps keep logs of tracked bugs and issues.

If the team already has some software modules, they could also conduct basic checks during the Environment Setup stage. While not necessary, evaluating if the product is ready for more advanced testing is still helpful.

5. Test Execution

The next phase of the STLC process is Test Execution. Finally, when all the preparations are complete, it’s time to move to the essential part of the process — the testing itself.

The team’s primary goal during this phase is to run as many tests as possible within the set timeframe. They should spot bugs, list them in the bugs report, and then submit the report to the development team.

The testing process may include functional, usability, and performance tests. Their order depends on the test plan and schedule. This diversity ensures that the testers will identify different types of bugs.

6. Test Cycle Closure

After completing all the testing, it’s time to move to the last phase of the STLC model — Test Cycle Closure. That’s where the testing team analyzes the results, evaluates their productivity, and shares suggestions for possible improvements.

The development team uses the report created during the previous stage to fix the bugs and errors spotted in the testing process. Then, the testing team runs the final tests. It’s critical to ensure they’ve fixed bugs and no new errors have appeared along the way.

The team also generates the final testing report for the client. It should be detailed and include the following things:

  • the time spent on testing;
  • the testing activities used;
  • the percentage of bugs found;
  • the total number of spotted and fixed errors;
  • the final recommendations.

Best Practices for the STLC Process

There are several ways to implement STLC in software testing. To help you choose the most relevant approach, let’s learn more about the best practices for the STLC process.

Continuous Testing

Continuous testing is the way to implement automation in STLC. The testing team develops automated tests integrated into the development process. Each time a product you update the product (change the code, release a new build, etc.), tests run automatically to spot possible bugs.

Risk-Based Testing

Risk-based testing sets priorities for the team based on potential risks. Instead of testing all products’ functionality, the team focuses on fragile areas more likely to contain defects. Risk-based testing may save the day if you’re short of time, budget, or resources. It helps achieve the desired results without significant investments.

Agile Testing

STLC in Agile differs from the standard approach. As Agile focuses on quicker and more flexible delivery, the testing process becomes blurry. The testing life cycle in Agile doesn’t start when a development phase ends. Instead, teams conduct it simultaneously with development to speed up the delivery time.

Benefits of Software Testing Life Cycle

Implementing the Software Testing Life Cycle might be challenging if your team is new to this approach. But, on the other hand, it makes testing much easier and more organized.

Here are the main reasons to implement STLC:

Improved Product Quality

STLC introduces testing earlier in the software development cycle. Thus, the testing team has more time to inspect the product and spot all the defects. Before adding a new feature, specialists inspect older ones for bugs. Such a thorough approach results in better product quality.

Faster Time-to-Market

With a clearly defined system and documentation, testers progress faster. Also, since STLC introduces testing earlier, testing and development teams spot and resolve issues on time. As a result, you may achieve a faster time-to-market.

Reduced Cost of Development

The earlier you discover bugs, the less you will spend to fix them. After all, when testing a product only after its full release, the number of defects often leads to extensive debugging or rework. In contrast, with STLC, the testing team spots issues earlier and fixes them before the final product version’s release. This approach considerably reduces the development costs.

Enhanced Customer Satisfaction

Testing teams have clearly defined goals for the product and the testing process. As a result, testers, developers, and the client are on the same page about the end expectations. It also facilitates tracking the testing progress.

Challenges in STLC Life Cycle

It wouldn’t be fair to explore the benefits of SLTC without uncovering its potential challenges. Being an efficient yet complex process, the Software Testing Life Cycle has several downsides:

  • It takes time to implement SLTC in your team.
  • People naturally tend to resist changes. So implementing a new approach requires additional effort.
  • SLTC needs many resources, from professionals to expensive infrastructure.
  • The more thoroughly you test, the more time the process takes. So if a project has tight deadlines, it might be challenging to use the SLTC approach.

Make Your STLC More Efficient with Softermii

If you’re looking for a team familiar with the STLC approach, Softermii’s experts are here for you! We know what it takes to deliver high-quality products and please clients with the result. Thanks to our extensive expertise in the field, we received the honorable title of “Best Company to Work With” by GoodFirms in 2023.

We know that complex solutions require meticulous testing, and we’ve built many successful products thanks to applying efficient approaches. One of the best examples is Expedipay, a P2P e-Wallet for the global market.

STLC life cycle

An e-Wallet should be easy to use and highly secure. After all, the customers’ money is at stake. To achieve that, Softermii focused on ensuring safe money transfers and timely fraud detection. Both features were well-tested to ensure the best performance.

When working on Streamotion, an e-commerce application with broadcasting features, we turned to a similar approach. In this case, we had to test the payment integration and live streaming thoroughly. Despite tight deadlines (7 months to build an MVP), Softermii delivered a working product without compromising its quality.

Testing life cycle in Agile

Last but not least, here’s the Proper app. Built for tenants and landlords, it included many sensitive features we had to protect. In particular, these were the payments integrations and communication content, like chat and location sharing, secured by end-to-end encryption.

Software testing cycle

Still, we managed to complete this project on time. The result? A successful solution that attracted 42 000 monthly active users in the first quarter.

If you want to achieve similar outcomes, don’t hesitate to ask us for help. Softermii can build a high-quality product for you, implement new features, perform UAT testing, and many more.


Building a secure and stable product isn’t a piece of cake. Creating a decent solution takes a lot of expertise and thorough testing. That’s why many software development teams use the Software Testing Life Cycle approach. With its help, they optimize their testing and QA process and achieve the best possible result within the available time frame.

If you’re looking for high-quality software testing services for your product, Softermii will gladly offer them! Instead of spending precious time finding and assembling a skilled team, you’ll instantly get expert testers. Start improving your product right away!

Frequently Asked Questions

What are the methodologies of the Software Testing Life Cycle?

The 4 STLC methodologies are:

  1. The Agile model. The testing is performed parallel to the development processes.
  2. The Waterfall model. Testing and development don’t overlap. Testing starts after the development process is complete.
  3. The V model. It’s a more modern version of the Waterfall model. It also doesn’t allow for simultaneous development and testing phases and links each STLC stage to SDLC.
  4. The Spiral model. This approach focuses on risk assessment and is relevant for large-scale projects.

How does the Requirement Analysis phase of STLC work?

At this stage, the testing team analyzes the product’s requirements to develop a testing strategy for each. The result of this phase is a report and a traceability matrix.

What happens during the Test Closure phase in STLC?

The Test Closure is the final phase of STLC. The testing team ensures that the development team has fixed all the bugs and no new flaws have emerged. Testing specialists also create detailed testing reports to share with the clients. Besides, they analyze and evaluate the team’s performance.

Why is Software Testing divided into separate stages?

Structuring the process into separate stages simplifies the testing team’s workflow, especially when working on large projects. As each STLC phase has its goals and deliverables, it’s much easier for testers to progress. Moreover, the rest of the software development team can track their progress.

What is the difference between STLC and SDLC?

STLC stands for Software Testing Life Cycle, while SDLC stands for Software Development Life Cycle. Both serve for building a software product. Check out this article to learn more.

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