Software Testing Lifecycle

In today’s fast-paced digital landscape, software has become the backbone of almost every industry. From mobile apps to e-commerce platforms, business decision-makers, and software development teams are under immense pressure to deliver high-quality products that meet customer expectations. This is where the Software Testing Lifecycle (STLC) comes into play. 

A Merit expert says, “Imagine building a skyscraper without conducting structural checks or taking safety measures—software development without proper testing is no different. It’s a recipe for disaster waiting to happen. STLC is the framework that ensures your software stands strong and functions flawlessly, just like a well-constructed building.” 

In other words, the Software Testing Lifecycle (STLC) is a structured framework for planning, executing, and managing software testing activities throughout the software development process. It ensures that software products meet quality standards, are reliable, and perform as expected. Some of the characteristics of STLC are; 

Phases of a STLC 

It is organised into well-defined phases, each with its own objectives and activities. These phases typically include requirements analysis, test planning, test design, test execution, defect tracking, and test closure. Each phase has a specific purpose and contributes to the overall quality of the software. 

STLC is not a one-time activity but an iterative and continuous process. Testing activities are carried out throughout the software development life cycle, from the early stages of requirements gathering to post-production maintenance. This ensures that issues are identified and addressed early, reducing the cost and effort required to fix them later. 

It is adaptable to different software development methodologies, such as Waterfall, Agile, or DevOps. It can be tailored to fit the specific needs and constraints of a project. For example, in Agile development, testing is integrated into each sprint, while in Waterfall, testing is a distinct phase following development. 

Objectives of the Software Testing Lifecycle 

Each phase of STLC has clear objectives and deliverables. For example, the test planning phase aims to define the scope, objectives, and resources required for testing, while the test execution phase focuses on executing test cases and capturing test results. This objective-driven approach helps ensure that testing is goal-oriented and systematic. 

It aims to achieve comprehensive test coverage. This means testing not only functional aspects of the software but also non-functional aspects like performance, security, and usability. Test cases are designed to cover various scenarios, including normal usage, edge cases, and error conditions. 

It promotes traceability between requirements and test cases. This means that each test case is linked back to a specific requirement or user story. This traceability helps ensure that all requirements are tested and provides transparency in demonstrating how the software meets its intended functionality. 

It includes defect tracking and management. When defects or issues are identified during testing, they are logged, prioritized, and assigned for resolution. This helps in systematically addressing and resolving problems, improving the software’s quality. 

It encourages continuous improvement in testing processes. After each testing phase, a retrospective analysis is often conducted to identify areas for improvement. This feedback loop ensures that testing practices evolve over time, becoming more efficient and effective. 

It promotes collaboration among cross-functional teams. Testers work closely with developers, business analysts, and other stakeholders to ensure a common understanding of requirements and quality goals. Collaboration fosters better communication and alignment of efforts. 

It emphasises thorough documentation of testing activities. Test plans, test cases, test scripts, and test reports are created and maintained to provide a clear record of testing efforts. This documentation serves as a reference for future testing cycles and audits. 

The 8 Phases of Software Testing Lifecycle 

Each phase in STLC has its own set of activities, objectives, and best practices. Let’s deep dive into how each phase contributes to the entire lifecycle. 

Phase 1: Requirements Analysis 


This is the foundation of effective software testing. Before you start testing, it’s vital to thoroughly analyse the project’s requirements. This helps in understanding what the software should do, which aspects are critical, and what success looks like. 

Testable Requirements 

Identifying testable requirements means selecting the parts of the project’s specifications that can be tested. Not everything is testable, and focusing on the right areas saves time and resources. 

Traceability Matrices 

Creating traceability matrices involves establishing links between requirements and test cases. This ensures that every requirement has corresponding test cases, which helps in measuring test coverage and ensuring that nothing is missed. 

Stakeholder Understanding 

Communication is key. During this phase, it’s crucial to establish a common understanding among all stakeholders, including developers, testers, and business analysts. Clear and shared expectations reduce misunderstandings later in the process. 

Phase 2: Test Planning 

Comprehensive Test Plan 

Think of this as your roadmap for testing. A comprehensive test plan outlines what you intend to do in terms of testing. It covers your test objectives (what you want to achieve), the scope (what’s in and out of scope for testing), test strategies (how you’ll approach testing), resource allocation (who does what), and risk assessment (what could go wrong and how to mitigate it). 

Phase 3: Test Design 

Effective Test Cases: Now that you have a plan, it’s time to design your test cases. Test cases are like scripts that testers follow to validate that the software works correctly. Effective test cases are detailed, and clear, and cover various scenarios. 

Deriving from Requirements 

Good test cases are closely tied to the requirements. You need to ensure that your test cases align with the expected behaviour outlined in the project’s specifications. 

Test Data 

Test data is the information your tests will use. It’s essential to create realistic test data to mimic real-world scenarios accurately. If you’re testing a shopping website, for example, you’d need data like product names, prices, and user profiles. 

Test Coverage 

Test coverage means making sure your test cases cover all aspects of the software, including different inputs, conditions, and scenarios. It helps ensure you’re not missing any crucial areas. 

Phase 4: Test Execution 

Executing Test Cases 

This is where the rubber meets the road. Testers execute the test cases designed in the previous phase. They interact with the software, input data, and compare the actual outcomes with expected results. 

Controlled Environment 

Testing needs a controlled environment to be reliable. The testing environment should mimic the production environment as closely as possible to get accurate results. 

Test Data Management 

Managing test data is crucial. You need to ensure that the data used for testing is consistent, relevant, and doesn’t interfere with other tests. 

Defect Reporting 

When testers encounter issues, they report them as defects. These defects are logged, describing what went wrong and how it deviated from the expected behaviour. 

Phase 5: Defect Tracking and Management 

Defect Identification 

Here, defects are identified through testing. Testers report issues like bugs, glitches, or any deviations from expected behavior. 


Not all defects are created equal. Prioritization is about deciding which defects need immediate attention and which can wait. Critical defects that affect core functionality usually get top priority. 


Defects have a lifecycle, from discovery to resolution. This phase involves tracking the status of each defect and managing the workflow for fixing them. 

Phase 6: Test Closure 

Completion Criteria 

Before wrapping up, you need to define what it means for testing to be complete. This involves setting criteria that indicate that all testing objectives have been met. 

Test Summary Reports 

You create a summary report that highlights what was tested, what defects were found, and whether the software meets the required quality standards. 

Stakeholder Sign-off 

The stakeholders review the testing results and provide their approval (sign-off) for the software to proceed to the next phase. 

Phase 7: Continuous Improvement 

Retrospective Analysis 

After each testing cycle, it’s crucial to look back and evaluate what went well and what could be improved. This retrospective analysis provides valuable insights for enhancing future testing processes. 

Feedback Loop 

The feedback collected from testing cycles is used to make ongoing improvements in the testing process, ensuring that it becomes more efficient and effective over time. 

Phase 8: Tailoring STLC to Development Methodologies 


STLC is flexible and can adapt to various development methodologies, such as Waterfall, Agile, and DevOps. Each methodology has its unique considerations, and STLC can be tailored to align with these approaches. 

Contextual Challenges 

This phase discusses the specific challenges and considerations when implementing STLC in different development methodologies. For example, Agile testing often involves frequent, smaller testing cycles within each sprint, while Waterfall testing typically occurs in distinct phases. 

By understanding and implementing each of these phases effectively, software development teams can ensure that their products are thoroughly tested, defects are managed efficiently, and the software meets quality standards and user expectations. 

Merit’s Expertise in Software Testing 

Merit is a trusted QA and Test Automation services provider that enables quicker deployment of new software and upgrades. 

Reliable QA solutions and agile test automation are imperative for software development teams to enable quicker releases. We ensure compatibility and contention testing that covers all target devices, infrastructures, and networks. Merit’s innovative testing solutions help clients confidently deploy their solutions, guaranteeing the prevention of defects at a very early stage.  

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