Software Testing Life Cycle (STLC)

The Software Testing Life Cycle (STLC) is a structured process that ensures every aspect of software quality meets user expectations and business requirements. It provides a systematic, step-by-step approach to verifying and validating a product before it reaches the market.

As an integral component of the Software Development Life Cycle (SDLC), the STLC focuses exclusively on quality assurance — ensuring that the software functions as intended, performs efficiently, and provides a seamless user experience.

Phases of STLC

We will explore the six key phases of the Software Testing Life Cycle (STLC) in detail below.

1. Requirement Analysis

The Requirement Analysis phase is the foundation of the Software Testing Life Cycle (STLC). During this stage, the QA team gains a comprehensive understanding of what needs to be tested and how testing should be approached to ensure complete coverage and product quality.

Objectives and Activities

In this phase, the QA team carefully studies the project’s specifications and identifies testable requirements. The main activities include:

• Reviewing the Software Requirements Document (SRD) and other relevant artifacts.
• Communicating with stakeholders to clarify business and technical expectations.
• Identifying ambiguities, inconsistencies, or gaps in requirements.
• Highlighting non-functional aspects such as performance, security, and usability requirements.
• Conducting feasibility and risk analysis to foresee potential challenges that may affect the testing process.
• Additionally, throughout this phase, the QA team maintains close collaboration with the BA (Business Analyst), PM (Project Manager), Team Leads, and sometimes clients to validate assumptions and ensure that requirements are fully understood.

2. Test Planning

The Test Planning phase is one of the most critical stages in the Software Testing Life Cycle (STLC). It serves as the blueprint for all testing activities, defining the strategy, scope, objectives, resources, timelines, and deliverables to ensure the testing process is well-structured and efficient.

Objectives and Activities

During this phase, the Test Manager or Test Leader designs a comprehensive plan that aligns with project goals and client expectations. The major activities include:

• Defining testing objectives and scope of work.
• Developing a test strategy, including the types, levels, and techniques of testing to be applied.
• Identifying testing environments and required resources (personnel, tools, and infrastructure).
• Determining test data requirements and test case design approach.
• Estimating testing effort, time, and cost.
• Defining test deliverables, milestones, and schedules.
• Assigning roles and responsibilities to the QA team.
• Reviewing and approving the final Test Plan before execution.

3. Test Case Development

The Test Case Development phase is where the QA team transforms requirements and test plans into actionable, detailed test cases and test data. This stage ensures that every functionality of the system can be thoroughly verified and validated against the defined requirements.

Objectives and Activities

In this phase, testers design, write, and review test cases that cover both functional and non-functional aspects of the software. The main activities include:

• Identifying all the test conditions and test scenarios to be validated.
• Writing clear, concise, and easy-to-understand test cases that align with business requirements.
• Creating or generating test data needed for each test case.
• Defining the expected results for every scenario to ensure consistency in verification.
• Reviewing and validating test cases with peers or test leads.
• Updating the Requirement Traceability Matrix (RTM) to map every requirement to corresponding test cases, ensuring full coverage and traceability.

4. Test Environment Setup

The Test Environment Setup phase defines the specific hardware, software, and network configurations required to execute the testing process effectively. This environment replicates the real-world conditions under which the application will run, ensuring that testing results are accurate and reliable.

Objectives and Activities

A well-prepared test environment is essential for minimizing defects caused by configuration errors and ensuring smooth test execution. The key activities in this phase include:

• Installing and configuring all required software, tools, and databases.
• Setting up servers, operating systems, browsers, and devices as per project requirements.
• Preparing user credentials, access permissions, and security settings.
• Validating that the environment is correctly configured before starting any test execution.
• Running smoke test cases to confirm that the basic functionality of the system is operational and the environment is stable.

5. Test Execution

The Test Execution phase is where all planned testing activities are carried out in the defined environment. During this stage, the QA team runs manual and automated test cases, records results, and reports defects to ensure that the software meets the specified requirements and functions as intended.

Objectives and Activities

This phase validates that the application performs according to expectations and business goals. The major activities performed include:

• Executing manual or automated test cases in the prepared environment.
• Comparing actual results with expected outcomes.
• Logging detected defects in the bug tracking tool, including severity and priority levels.
• Performing retesting to verify fixed defects.
• Conducting regression testing to ensure that recent changes haven’t affected existing functionality.
• Collecting, analyzing, and documenting test results.
• Preparing and sharing progress and defect reports with the project manager and stakeholders

6. Test Closure

The Test Closure phase marks the completion of the Software Testing Life Cycle (STLC). In this final stage, the QA team reviews, analyzes, and documents the outcomes of all testing activities to ensure that project objectives and quality standards have been achieved. This phase also serves as an opportunity to reflect, evaluate, and improve future testing processes.

Objectives and Activities

The Test Closure phase involves formally wrapping up the testing effort, ensuring that all deliverables are completed, and all defects are addressed. The key activities include:

• Preparing a comprehensive Test Summary Report that includes executed test cases, pass/fail statistics, and defect details.
• Ensuring that all reported defects have been properly tracked, fixed, retested, and closed.
• Cleaning up the test environment and releasing resources such as test data, test scripts, and environments.
• Archiving all test artifacts (test plans, cases, data, and reports) for future reference and compliance.
• Conducting a retrospective meeting to evaluate the overall testing process — identifying strengths, weaknesses, and opportunities for improvement.
• Sharing knowledge and lessons learned with all stakeholders to enhance the efficiency of future projects.

Software Testing Life Cycle (STLC) Overview

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STLC vs SDLC comparison table