The Software Testing Life Cycle (STLC): A Complete Guide

The software testing life cycle (STLC) plays a foundational role in testing your applications efficiently and effectively. In this blog, we cover everything you need to know about the STLC and building this strong base for scalable test automation. In no time, you will have a much better foundation to better organize and improve your testing strategy. 

Keep reading or jump ahead to the section that interests you most: 

Table of Contents: 

• What is the STLC? 
• Advantages of the STLC 
• STLC vs. SDLC 
• Phases of the STLC 
• The Compatibility of the STLC With Agile Development 

What is the STLC? 

STLC is an acronym for the Software Testing Life Cycle. The STLC describes the series of steps taken during the process of ensuring software or app quality. STLC is also known for its integral role in the Software Development Life Cycle (SDLC). 

Advantages of the STLC 

The STLC helps teams stay organized and ensure that they are meeting project requirements. By clearly defining expectations, time constraints, and goals for each aspect of the project, teams can leverage the STLC to increase effectiveness and overall consistency.  

The STLC also helps teams make sure that new features are sufficiently tested and passed before adding new features to the application. 

Advantages of the STLC include: 

• Shift-left testing. By keeping teams on track, the STLC helps teams test earlier in the development cycle.   
• Easier tracking. By following a set of well-defined goals and phases, it is easier to track progress.   
• Faster bug detection. By testing earlier in software development, it is simpler for teams to detect and resolve issues more quickly.  

STLC vs. SDLC  

STLC stands for the software testing life cycle, while SDLC refers to the software development life cycle. While the two overlap, the STLC is only a part (albeit a very critical part) of the activities performed during the software development process.  

One important goal of the STLC is to incorporate testing more and more into the software development life cycle. By testing as early as possible, development teams can focus more on the goals of the SDLC, namely gathering requirements and creating corresponding features.  

Phases of the STLC 

There are six phases of the STLC: 

• Requirement analysis. 
• Test planning. 
• Test case development. 
• Environment setup. 
• Test execution. 
• Test cycle closure. 

Each phase consists of entry and exit criteria, which defines when a phase can start and end, as well as any actions or deliverables that are needed for each phase. Let us take a closer look at each one. 

Requirement Analysis 

During the Requirement Analysis phase of the STLC, teams determine testing requirements for their application, whether it is a new feature or adapting to a growing customer need. At this stage, teams decide whether they can use test automation to validate these requirements, which may be functional or non-functional (e.g. performance testing or accessibility testing).   

In this phase, teams gather two types of criteria:  

• Entry Criteria: Acceptance criteria, client requirements, and the intended product architecture. 

• Exit Criteria: Automation feasibility report and a requirement traceability matrix (RTM), which is a document that demonstrates the relationship between requirements and other artifacts. 

Test Planning 

The Test Planning phase of the STLC includes defining and implementing a test strategy. This stage also estimates the costs and efforts needed to complete testing within the allotted amount of time. Activities that happen during the Test Planning phase include selecting testing tools, preparing test plan documents for different types of testing, and fulfilling training requirements as needed. 

• Entry Criteria: Reporting the test strategy before it is implemented. 

• Exit Criteria: Approval on test plan costs and risks from stakeholders. 

Test Case Development 

This STLC phase is relatively self-explanatory. In this phase, testers create the actual test cases that will validate any new functionality or feature. These test cases will also include any automation scripts, as well as data, execution conditions, and any expected results.  

These test cases should be transparent to the entire team, and adaptable to any changes that may come later in the cycle.  

• Entry Criteria: Approval of the testing timeline. 

• Exit Criteria: Test case and automation script approvals. 

Environment Setup 

The next phase of the STLC includes configuring and deploying your test environment. This phase may include a mix of open-source frameworks such as Appium, Flutter, or Selenium, and commercial solutions like Perfecto.  

After the environment is deployed, teams run smoke tests to ensure that the environment is running as intended. 

• Entry Criteria: Defining a project architecture and system design. 

• Exit Criteria: Approval for the test environment and test cases. 

Test Execution 

This phase is where teams finally get to see some action. Testers begin running test executions on their fully set-up test environment. They can then compare the expected results that they indicated in the Test Case Development stage with actual test results, and make changes as needed in collaboration with the development team. 

• Entry Criteria: Approved test environment and test cases. 

• Exit Criteria: Documented test results to share with developers and other stakeholders. 

Test Cycle Closure 

Finally, we get to the last phase of the STLC – Test Cycle Closure. This is the stage where teams analyze the test report describing the test executions that just took place. The Test Cycle Closure stage is also the stage where teams review other important test metrics, such as test coverage, time spent, bugs found, and total costs. 

• Entry Criteria: Test results from all the earlier phases. 

• Exit Criteria: Approved test reporting with next steps. 

The Compatibility of the STLC With Agile Development 

As teams are looking to release new features as quickly as possible, organizations are adopting agile development methods to adapt quickly to changing needs and continuously release high-quality software at a fast rate.  

Following the STLC in an agile environment is a great way to ensure that teams communicate and stay on track with meeting requirements. In an agile organization, testing and development do not work in silos; rather they are grouped together as one team. By following the clearly outlined guidelines of the STLC, testers and developers are better equipped to collaborate frequently and perform better change and risk management. 

Bottom Line 

The STLC is an important foundational piece of successful application testing. By running your testing workflow in a more organized manner, teams can make their testing more efficient and effective.  

Another great way to make your testing more efficient is by using the proper testing tools. With a test automation platform like Perfecto, you can execute all aspects of the software testing life cycle from one place. 

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