What Is the Software Testing Life Cycle? A Complete Guide

The software testing life cycle is the sequence of activities that happen during software testing. By employing a sane software…

Software Testing Life Cycle
By Testim,

The software testing life cycle is the sequence of activities that happen during software testing. By employing a sane software testing life cycle, an organization ends up with a quality strategy more likely to produce better results. Why is this so important, though? It all boils down to customer satisfaction. Presenting a perfect product to the customer is the end goal of every organization.

Nothing puts off customers more than bug-filled user experience. So when enterprises realized this, they began to include testing as a mandatory part of the SDLC. Since then, testing has become an integral part of every organization.

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With agile, an application’s testing life cycle became more process-oriented and versatile. Usually, the entire focus of an enterprise is on the software development life cycle (SDLC) alone. And they consider testing a part of that process. But it’s high time that firms realize that software testing has a life cycle of its own. We’ll start with some fundamentals, by defining the software testing life cycle and comparing it to the software development life cycle. As you’ll see, despite being intimately related, these two terms refer to two different concepts.

This is a summary of what we’ll cover:

  • What Is the Software Testing Life Cycle?
  • What are STLC and SDLC?
  • What Is the Role of STLC in SDLC?
  • What Are the Phases of Testing?
  • What Are the Entry and Exit Criteria for Testing?
  • Conclusion

So let’s dive right in!

What Is the Software Testing Life Cycle?

A life cycle is the sequence of changes an entity goes through from one form to another. Many concrete and obscure entities go through a series of changes from start to finish. When we talk about the software testing life cycle, the software is an entity. The software testing life cycle is the process of executing different activities during testing.

These activities include checking the developed software to see if it meets specific requirements. If there are any defects in the product, testers work with the development team. In some cases, they have to contact the stakeholder to gain insight into different product specs. Validation and verification of a product are also important processes of the STLC.

What are STLC and SDLC?

The complete journey of a product from its start to becoming the final product is taken care of by SDLC. Among the various phases of SDLC, testing is one of the most important. Software testing is a part of SDLC. And this part has got its own life cycle—STLC. So how is SDLC different from STLC?


  • Focus on building a product
  • A parent process
  • Understanding user requirements and building a product that is helpful to users
  • SDLC phases are completed before testing
  • End goal is to deploy a high-quality product that users can use


  • Focus on testing a product
  • A child of SDLC process
  • Understanding development requirements and ensuring the product is working as expected
  • STLC phases start after phases of SDLC are completed
  • End goal is to find bugs in product and report to the development team for bug fix

These are the basic differences between SDLC and STLC. Now, let’s understand STLC in depth. 

What Is the Role of STLC in SDLC? 

In the previous section, we saw that the end goal of SDLC is to deploy high-quality products. How do we measure high quality? How can we achieve it? The user experience is directly proportional to the quality of a product. One of the major things to achieve this is to make sure that the product is working smoothly and as expected. That’s where STLC comes in. The role of STLC in SDLC is to identify any part of the product that’s not working smoothly or as expected and inform the development team for updates. 

Now that we have the gist of what the software testing life cycle is, let’s take a look at why it’s essential. Even if a firm has the best programmers and developers, they are bound to make mistakes. The main role of STLC is to find those mistakes and get them fixed. The main goal of conducting an STLC is to maintain product quality.

From planning and research to execution and maintenance, every phase plays a crucial role in testing a product.

STLC is all about assuring the product’s quality. Every application has different attributes such as reliability, functionality, and performance. And STLC aids in enhancing these attributes and facilitates the delivery of an ideal end-product.

A high-quality product results in lower maintenance costs in the long run. The stability of an application or software is a must to entice new users. Apart from that, consistently reliable products also help keep existing clientele. For a product to stay in the realm of business, it’s important to focus on each phase of the STLC.

What Are the Phases of Testing?

Validating every module of software or application is a must to ensure product precision and accuracy. Since software testing itself is an elaborate process, testers carry it out in the following phases:

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

Complexities can pop up if testing lacks organization. The complexities may include unresolved bugs, undetected regression bugs, or in the worst case, a module that skipped testing because the deadline got closer.

Each phase of the STLC has a specific goal and deliverables. It involves the initiation, execution, and termination of the testing process.

Let’s take a look at different phases of the software testing life cycle in detail.

1. Requirement Analysis

Your valuable software testers have to view, study, and analyze the available specifications and requirements. Certain requirements produce outcomes by feeding them with input data. These requirements are testable requirements. Testers study both functional and non-functional requirements. After that, they have to pick out testable requirements.

Activities in this phase include brainstorming for requirement analysis and identifying and prioritizing test requirements. They also include picking out requirements for both automated and manual testing. There are a few things you have to test even if not explicitly mentioned. A click on an active button should do something, a text field for phone number shouldn’t accept alphabets submitted.

These things are universal and should always be tested. But the requirement analysis phase is about knowing more specific details about the product. You need to learn how the product should be in its ideal state. This phase generates as deliverables a detailed requirements report, besides analysis of test automation feasibility.

Another important deliverable generated in this phase is a requirements traceability matrix. What’s this?

“Traceability” here means the ability to trace back artifacts from their requirements. For instance, having traceability in the software development process means that the organization should be able to trace each commit in its codebase back to its original requirements. When it comes to software testing, you want to be able to trace back testing activities to their original requirements.

That way, you reduce waste, by ensuring that every testing activity is connected to a requirement that generates value for the customer. To sum it up:

  • Understand the expected output from the product.
  • Identify any loopholes in the specifications.
  • Collect priorities.
  • Perform automation feasibility checks.

2. Test Planning

The second step is test planning, and the QA team creates this plan after analyzing all the necessary testing requirements. They outline the scope and objectives after understanding the product domain. The team then analyzes the risks involved and defines time schedules and testing environments to create a strategy.

After that, management finalizes the tools and assigns roles and responsibilities to individuals. An approximate timeline is also defined by which the testing of each module should be completed. The most important delivery generated in this step is the test plan, which is a document describing the motivation and details of the testing activities for a given project. To sum it up:

  • Prepare test plan documentation.
  • Estimate time and efforts.
  • Finalize tools and platform.
  • Assign tasks to teams and individuals.
  • Identify training requirements

3. Test Case Designing and Development

After development and planning, it’s time to let the creative juices flow! Based on the test plan, testers design and develop test cases. Test cases should be extensive and should cover almost all the possible cases. All the applicable permutations and combinations should be gathered.

You can prioritize these test cases by researching which of them are most common or which of them would affect the product the most. Next comes the verification and validation of specified requirements in the documentation stage. Also, the reviewing, updating, and approval of automation scripts and test cases are essential processes of this stage.

This phase also includes defining different test conditions with input data and expected outcomes. So, the main deliverables produced in this phase are the actual test cases organized in their test suites. To sum it up:

  • Research and gather possible actions on the product.
  • Create test cases.
  • Prioritize test cases.
  • Prepare automated scripts for test cases.

4. Test Environment Setup

Testing activities need certain environmental factors—such as servers, frameworks, hardware, and software—for executing developed test cases. And it’s mandatory to smoke test and to equip your testers with bug reporting tools. In the developer community, it’s common to hear “it ran on my system, but it’s not running on yours”.

Hence it is important that your test environment covers all the environments that the user would use. For example, some feature that works in Google Chrome doesn’t work in Internet Explorer. A feature might work smoothly on 4 GB RAM but might create issues with 1 GB RAM. Research on environments used by end-users would help you prioritize your test environments.

The main deliverable in this stage is a complete strategy for test environment management.

It’s the job of the QA manager supervising the team to take care of setting up the test environment. To sum it up:

  • Understand minimum requirements
  • List down software and hardware required for different levels of performance. 
  • Prioritize test environments
  • Setup test environments
  • Smoke test the built environments

5. Test Execution

An application is ready for testing once the team is done with all the previous phases. According to the test plan, the testers execute test cases. They also identify, detect, and log the defects, thus reporting the bugs. The team is also responsible for comparing expected results with the real outcome. If any bugs are found, they need to be documented to pass it on to the development team for a fix. 

Once the development team removes a bug, regression testing begins. Regression testing is to ensure that the software or application works even after deploying a change. When testing after a bug fix, test the complete product again. Because a fix for a bug could create a bug on some other part of the product.

And because the same tests need to be run again and again after every fix and deployment, it’s recommended to use scripts or automated testing tools. We could say the main deliverables in this phase are the test results, which, ideally, should be validated and communicated in an entirely automated manner. To sum it up:

  • Run test cases.
  • Identify deviation from expected behavior of the product.
  • Log failed cases with details
  • Test again after bug fixes.

6. Test Closure

And that brings us to the last stage of the STLC: test closure.

The end of test execution and delivery of the end product marks the onset of the test closure phase. The QA team checks the test results and discusses them with other team members. Some other factors they consider are product quality, test coverage, and project cost. If there’s a deviation from estimated values, further analyzes can be done to identify what didn’t go as expected. 

It’s an essential practice for testers to come together and discuss the conclusion after testing. Any issues faced during testing, flaws in strategies can be discussed here. You can also work on coming up with a better approach for testing based on the learnings during testing. If you follow DevOps or canary release practice, testing is frequent. You can decide on how often to send reports and what details to mention while sending reports to different stakeholders. 

Apart from that, the team also considers test metrics, the fulfillment of goals, and their adherence to deadlines. Once they have a total grasp on what happened, they can evaluate the entire testing strategy and process. To sum it up:

  • Verify that all tests are completed
  • Evaluate factors such as quality, test coverage, timeline, and cost
  • Document the conclusion
  • Discuss the learning and find out if the testing process can be improved
  • Prepare test closure report 

What Are the Entry and Exit Criteria for Testing?

All six phases of a software testing life cycle have entry or exit criteria associated with them. Testers need to finish executing the test cases within a fixed time. Also, they need to maintain the quality, functionality, and efficiency of the end product. Therefore, defining entry and exit criteria is a must. That’s what we’ll do now.

Entry Criteria

Entry criteria state which requirements the team has to take care of before starting the testing procedure. Before testing begins, it’s mandatory to cross off all requirements.

There are some ongoing activities and conditions that have to be present before testing begins. First, you need input from the development team. You’ll also want to examine the test plan, test cases and data, the testing environment, and your code.

Exit Criteria

Exit criteria state the requirements and actions to complete before the testing ends. In other words, they include items to cross off the task list and processes to complete before testing comes to a halt.

Exit criteria will include the identification of high-priority defects. You’ll need to get those fixed right away. Testers have to pass different test cases and ensure full functional coverage.


Simply identifying errors in the last stage of an SDLC is not an efficient practice anymore. There are various other daily activities a firm has to focus on. Devoting too much of your precious time to testing and fixing bugs can hamper efficiency. After all, you’ll take more time to generate less output.

To ease the testing process, it’s important to make efficient use of time and resources. Following a systematic STLC not only results in quick bug fixing but it also enhances the product quality. By increasing customer satisfaction, you’ll enjoy an increased ROI and improved brand presence.

What should your next steps be, then? Well, education is always a great next step. So, we suggest you start by learning more about software testing in general. 

Here are some blogs you might be interested in:

Education, despite being essential, can only take you so far. At some point during your software testing journey, you’ll have to learn about test automation tools and pick the one best suited for your organization. When this comes, we invite you to take a look at Testim Automate, an AI-powered test automation tool that solves two of the biggest challenges in test automation: difficult test case authoring and heavy test maintenance.

Due to Testim’s hybrid approach to authoring test cases, everyone in the team can contribute to the testing strategy. And thanks to its innovative smart locator strategy, fragile end-to-end tests are a thing of the past.

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