Skip to main content

Similar to the legendary detective Sherlock Holmes unraveling perplexing cases, the software testing life cycle (STLC) demands meticulous investigation and deduction. 

Holmes would methodically gather clues, analyze evidence, and draw conclusions; software testers embark on a journey through key phases, following a systematic path to uncover potential defects and ensure a seamless end product.

In the digital age where software runs our world, it's imperative to approach software testing with the same level of scrutiny and astuteness that Mr. Holmes would apply to solving an intricate mystery.

In this context, let's embark on a journey through the software testing life cycle—one that mirrors Holmes' relentless pursuit of truth and order. How can you ensure the delivery of software that stands up to the scrutiny of modern technology? Channel your inner Sherlock Holmes and join our investigation.

What Is The Software Testing Life Cycle (STLC)?

The software testing life cycle (STLC) is an essential part of the overall software development process. Software testing helps ensure that the final product is high-quality, robust, reliable, and free from defects. The STLC defines, plans, and executes the steps that go into testing to improve the quality of software products.

Just as Sherlock Holmes meticulously analyzed every clue to uncover the mysteries that crossed his path, the STLC delves into the intricacies of software quality. Fundamentally, the STLC is a systematic approach to ensure that software quality meets the desired standards and is free from defects. It is an ongoing process with multiple phases, each vital in delivering reliable and efficient software.

How Does the STLC Compare To The Software Development Life Cycle (SDLC)?

The STLC is an essential part of the overall software development life cycle (SDLC). It's the part that tests and validates that the software application works as expected and that any bugs, risks, flaws, or mistakes are fixed before the software is released to users. It can begin as soon as software requirements have been identified. 

Why Do You Need STLC In The Software Development Life Cycle?

There are many types of software testing, and each is designed to validate that the software meets specific project requirements—functional, nonfunctional, quality, security, and more. The STLC is our detective's toolkit, providing a structured way to help create the right testing environment to assess software efficiently, identify bugs, flaws, and risks, and deliver high-quality software that people enjoy using. Holmes starts his investigation as soon as the clues are identified; the STLC begins its journey from the moment software requirements are set.

Discover what’s new in the QA world.

Discover what’s new in the QA world.

  • By submitting this form, you agree to receive our newsletter and occasional emails related to The QA Lead. You can unsubscribe any time. For more details, please review our Privacy Policy. We're protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
  • This field is for validation purposes and should be left unchanged.

How Do You Choose the Right Tools For Your STLC Process?

There are many software testing tools on the market, and you need to pick ones that fit your particular testing use case(s). For more insight on choosing the right tools, consult our list of the 19 Best Software Testing Tools For QAs.

What Are The Main Benefits Of The STLC?

Much like Holmes' pursuit of consistency and precision, the STLC systematic approach helps QA teams achieve greater consistency, efficiency, and effectiveness. This approach helps ensure that testing goals, project requirements, and testing timelines are defined and verifies that all conditions and functions are tested and validated before deployment.

What Are the Key Phases Of The STLC?

1. Requirement Analysis Phase

The STLC kicks off with the requirement analysis phase. How did Sherlock Holmes collect evidence? By interviewing witnesses to establish the foundation of his investigation. Similarly, testing teams work closely with business analysts, developers, and stakeholders to understand the project’s objectives, features, and functional testing requirements. These form the requirements traceability matrix (RTM), which validates that all requirements and functionality are tested. 

Entry criteria: Requirements document, acceptance criteria, application architecture

Exit criteria: Approved RTM and test automation feasibility document

2. Test Planning Phase

In this phase of STLC, the testing team defines the test strategy, plans, and objectives, similar to how Holmes formulates a strategy for solving a case. Key elements include determining the types of testing, identifying test tools and environments (including manual and automated testing), defining test coverage, and allocating resources.

Entry criteria: Requirements document, RTM, test automation feasibility report

Exit criteria: Approved test plan document and effort estimation document

3. Test case development phase

In this phase, the team develops test cases to validate the software’s functionality, performance, and security. Analogous to Holmes identifying the main areas his investigation will focus on, a well-structured test case includes the test scenario, test steps, expected results, preconditions, and post conditions.

Entry criteria: Requirements document, RTM, test plan, automation analysis report

Exit criteria: Detailed test cases and data

4. Test environment setup phase

The setup phase helps eliminate any hindrances to a successful test. Holmes meticulously arranges his surroundings before diving into a complex case; software testers carefully orchestrate the testing environment. QA teams create the controlled stage for their investigation–only, in their case, the mystery to unravel is the reliability and quality of the software they’re testing.

Entry criteria: System design and architecture, environment setup plan

Exit criteria: Verification that the test setup works as planned, test data set up, successful smoke test

5. Test execution phase

The heart of the STLC involves running the test cases according to the test plan and recording the results. Think of Holmes' on-the-ground investigations, where he gathers evidence and puts his theories to the test. The goal is to find defects and understand the software’s behavior and performance under different conditions. Any discrepancies are documented in a defect management system, which assigns, prioritizes, and tracks defects to resolution. Once the development team fixes a defect, the QA team retests to ensure the issue is successfully addressed.

Entry criteria: RTM, test plan, test scripts and cases, ready test environment, test data, unit or integration test reports

Exit criteria: Completed RTM, updated test cases, defect reports

6. Test cycle closure phase

The testing team compiles all test results, defect reports, and other relevant documentation into a test summary report. It includes an overview of the testing activities, the status of the test cases, and the overall product quality. And just like Holmes closes a case and provides a report of the investigation’s findings, the test summary report enables informed decisions about the software’s readiness for release.

Entry criteria: Completed testing, test results document, defect logs

Exit criteria: Test closure report and test metrics

What Methodologies Are Used In The STLC?

STLC models are similar to general software development life cycle models.

The agile model is an iterative and flexible approach that involves short testing cycles called sprints. It allows continuous feedback and changes to be incorporated throughout the software development process, making it well-suited for projects with evolving requirements. Like Holmes, who collaborates with his loyal Dr. Watson, it’s often used with DevOps.

The waterfall model follows a linear path, akin to Holmes' unwavering pursuit of a singular goal. This method requires one testing phase to complete before the next one begins. While it offers clarity and simplicity, it may not be the best fit for projects with changing requirements.

The V model divides the testing life cycle into two phases: verification and validation, with substeps within each. Often, Holmes dissects a case into smaller, manageable pieces in the same way. Like waterfall, one step must be completed before the next one begins. Its rigidity can slow the testing process, but it works well for smaller projects and those where improving communication and coordination between developers and testers is critical.

The spiral model combines elements of the waterfall and agile approaches. It is characterized by its iterative nature, where development occurs in cycles, or "spirals." Each spiral represents a phase in the testing process. Its explicit focus on risk management sets the spiral model apart. It is particularly valuable for complex projects with evolving requirements where, much like Homes’ cases, it demands a delicate equilibrium between risk and flexibility.

Closing the Case: Mastering The STLC for Superior Software Quality 

Embracing the detective mindset within the software testing process can help organizations uncover potential issues, streamline their workflows, and deliver software products of the highest quality. So, put on your metaphorical deerstalker hat and approach the software testing life cycle as a thrilling adventure, just like the great detective himself. 

For more insights on software testing, subscribe to the QA Lead’s newsletter and be the first to read new blog posts about testing and quality.


What are entry and exit criteria?

Entry and exit criteria help define the conditions or deliverables that must be met before proceeding to the next phase of testing or concluding a phase. They help ensure testing activities are well-planned, effective, and aligned with the project’s goals.

In which phase of the system life cycle is software testing performed?

The STLC can begin when the development team identifies the software project’s requirements. Integrating testing throughout the SDLC can help prevent mistakes and reduce costs. In a waterfall model, the STLC begins after the software is developed and before it is deployed for users in the production environment.

What makes a good QA team?

A good QA team member is collaborative, detail-oriented, familiar with testing tools, endlessly curious, and committed to quality. See 12 Key Quality Assurance Skills & Competencies to learn more about what it takes to be a first-class QA person.

Vicki Walker
By Vicki Walker

Vicki Walker is a veteran technology writer and editor. She has more than 20 years of experience in technology publishing for companies including Red Hat,, Dark Reading, SAP, BlackBerry, and Network Computing. She is a graduate of the University of Florida and earned a certificate in core public health concepts from the University of North Carolina at Chapel Hill. She lives in Charlotte, N.C. with her husband, a dog, and two cats, and avidly follows Carolina Panthers football.