Software Testing Life Cycle (STLC) in Software Testing

Software Testing Lifecycle (STLC) is a way for testers to follow a series of steps to deliver a bug-free application that stays true to the user requirements. STLC in testing is a systematic approach with the objective of meeting software quality requirements. While it sounds similar to Software Development Lifecycle (SDLC), it differs largely from the concept. Both SDLC and STLC are two different methods in IT, and we will mention their differences in the later section. We will discuss more on this topic and define all the related terms to STLC. Let’s begin.

Test Management by Testsigma streamlines every STLC phase from requirement analysis to closure, so that your team delivers high-quality software faster, with full traceability, collaboration, and control.

Start TestingExplore Atto’s Capabilities

What is Software Testing Life Cycle (STLC)?

STLC is a systematic approach to testing, which involves verifying an application to check if it meets the requirements and is free of faults. It follows a series/phase of steps where every phase has its objective and deliverables, and the software must fulfill those goals to move on to the next step. The purpose of STLC in testing is to provide a high-quality, reliable, and stable application that stays true to the requirements of the customers. The phases of STLC are Planning, Analysis, Design, Environment Setup, Execution, Closure, and Defect Retesting. We will discuss each one of these steps in detail in the coming sections.

Characteristics of STLC

STLC characteristics define the scope of testing and its importance as a part of SDLC. Here are some of them:

• STLC is a fundamental section of SDLC, but it only consists of testing phases.
• The phases of STLC start soon after requirement documents are defined.
• STLC follows a series of steps in a sequential manner to yield quality software that functions as per the requirement document.

In STLC, before starting any phase, you will have to analyze and define the scope of testing, the entry and exit criteria, and the test cases. All this helps to decrease the test cycle time and enhance product quality. And after the development phase is complete, the testing team can begin the execution using the test cases.

Importance of Software Testing Life Cycle

Quality and dependability of software products are ensured by the Software Testing Life Cycle (STLC). Let me tell you why this is important:

• Early Detection of Defects:  The STLC initiative takes place at an early stage of software development. This means that bugs can be caught and eliminated before they grow into bigger issues later down the line. This approach saves time and resources as it deals with problems when they are less costly to address.

• Improved Quality: When all components of the software are tested to ensure they meets the required standards including performance and security – it helps improve quality.

• Risk management: Risk assessment and mitigation strategies are part of STLC. When potential risks are identified and worked on during the testing phase, this helps reduce the occurrences of software failure or unexpected behavior in production.

• Clear Testing Goals: For each phase of STLC, there are particular deliverables and goals— like the test plans, test cases and test reports. This clear understanding makes sure that the tests are done in an organized way which helps to deliver better outcome from the testing process.

• Cost Efficiency: Although adoption of STLC is time and resource consuming at the outset, it eventually leads to curtailment of expenses related to defects that surface post release. It costs a lot less to address issues if they are discovered and dealt with during the development phase than after the software has been rolled out.

• Customer Satisfaction: When a properly tested software is delivered, it not only does what the customer expects in terms of functionality, reliability and performance but also wows user satisfaction, leading to trust by end users on the software system.

• Compliance and Standards: If these are met by the software, it adheres to STLC, thus making sure that the software is compliant with required regulatory standards and guidelines. This can be very important in industries such as healthcare, finance, or aerospace where the issue of reliability and safety of software is crucial.

• Continuous Improvement: STLC helps make things better by giving feedback at different points. This allows us to learn from testing and use that to improve development processes, tools, and frameworks.

What is the Role of Software Testing Life Cycle?

The role of STLC is primarily to identify issues in the application as soon as possible and record it for developers to understand and resolve. For testers, STLC assists in the following:

• Fine-tuning the agile process, making it effective and efficient for cross-team communication
• Clearly defining the deadlines for project testing
• Properly documenting the goals and objectives of every project and following through consistently
• Ensuring and verifying that the objectives of all the phases are accurately met
• Testing each and every feature of the software before passing it for adding more features
• Analyzing the tasks that can be automated to improve the testing quality

Here are some of the common activities in STLC that you would have to execute:

• Analyzing all the requirements of the project
• Creating a document that measures the progress of the testing
• Identifying the testing types and techniques you need for the project at hand
• Determining which environment to test your application on
• Prioritizing the right tasks and understanding which of those can be automated
• Listing down the automation tools you need to run your STLC tests

Some of the popular automation tools you can use are Testsigma, Selenium, Cypress, and TestNG. All of these have different features and provide varying services to your testing needs. You can choose the one that complements your project.

Methodologies of Software Testing Life Cycle

There are a few main methodologies used in STLC:

1. Waterfall Model

In the waterfall model, software development progresses sequentially through defined phases (requirements, design, implementation, verification, maintenance). STLC aligns with this by having distinct testing phases corresponding to each development phase. For example, testing starts after the completion of the implementation phase and continues through to deployment.

2. Agile Model

Agile is the enabler of development through iterations and short cycles of testing referred to as sprints. The Agile STLC differs significantly from other models by being more continuous, integrating testing activities throughout the development process. In each sprint, testing tasks — such as writing test cases, executing tests, or reporting defects — are completed incrementally. This way any issues that appear can be captured early during the sprint cycle and addressed promptly.

3. Scrum 

Scrum is a particular Agile framework, characterized by the fact that development work is organized into iterations with fixed durations which are termed sprints. The STLC in Scrum engages the whole team — developers and testers alike — in sprint planning, daily stand-ups, and sprint reviews. Testing tasks are interleaved across the sprint timeline. Each sprint,  primary focus is on ensuring that the product has a potentially shippable increment by the end of the sprint.

4. DevOps

DevOps is the junction where software development (Dev) and IT operations (Ops) meet and play well together to streamline flow and enhance harmony. The STLC within the realm of DevOps stresses on one core principle— continuous testing intertwined with continuous delivery (CI/CD). Testing components are automated when feasible, and these automated test scripts find themselves a cozy spot within the CI/CD pipeline. Their responsibility? To provide prompt feedback without delay, catching hold of any lurking defect at the earliest instance possible.

5. Iterative Model

The Iterative model is similar to Agile in the sense that it includes iterative development cycles. In these cycles, software is developed, tested and refined in each successive iteration: the testing activities are an integral part of STLC in this model. These activities support iterative testing, thereby allowing to refine the product incrementally through each iteration.

6. V Model (Verification and Validation model)

The V-Model is a system that conducts the development and testing activities side by side. With each stage in the software development process, a corresponding stage is identified within the STLC in order to carry out consistent testing practices (unit testing, integration testing, system testing, acceptance testing) which consequently ensure complete verification and validation of the product at various levels.

Advantages and Best Practices of STLC

STLC makes sure to everything is tested thoroughly, catching problems early on to make sure the product is reliable and top quality. This saves money on fixing things later. 

STLC also helps reduce risks and keep customers happy, which helps in improving and meeting industry standards. 

Plus, STLC helps teams work together better and be more efficient.

What Are Entry and Exit Criteria in STLC?

STLC must comply with entry and exit criteria to be termed as successful. Ideally, the QA team takes care of this point and only begins/completes the next STLC phase after both criteria are met. Both these criteria are defined for each phase of STLC.

Entry Criteria

Entry criteria for an STLC phase are to undertake all prerequisite conditions that must be met before testing starts. All the documents, with the necessary information regarding testing, should be available before initiating any of the STLC phases. For example, to begin with, creating test cases, you must have the user requirement document, a complete understanding of the application flow, and the test plan document. This is the entry criteria for developing and executing test cases.

Exit Criteria

Exit criteria are all the information/items that must be available and completed before concluding a phase. It includes all the actions, tasks, documents, and test elements that need to be over before marking the phase complete and moving on to the next one. One example of exit criteria can be verifying if the user requirements are proper and all the risk-associated areas of an application are thoroughly tested.

6 Phases of STLC Phases

STLC consists of 6 phases where each has its entry-exit criteria and comes with associated activities and deliverables. Entry-exit criteria define when the phase starts and ends. Activities and deliverables define the actions taken within the phase and the results received. You can execute some of these phases together while others run more independently. These are the 6 phases of STLC:

1. Requirement Analysis

In this phase, teams gather and import requirements, ensuring they are testable and clearly defined. With Test Management by Testsigma, you can map requirements to test cases for complete coverage and clarity before planning begins.

2. Test Planning

Here, the test approach is designed, including scope, risk areas, resources, and scheduling. Test Management by Testsigma centralizes planning, making it easy to assign roles, define entry/exit criteria, and align the team.

3. Test Design & Case Creation

Test cases and suites are created, prioritized, and reviewed for accuracy. Test Management by Testsigma allows teams to reuse, version, and organize cases effectively, ensuring efficiency and consistency.

4. Environment Setup

The required test environments and configurations are set up and validated. With Test Management by Testsigma, you can document configurations, manage versions, and link them directly to test executions.

5. Test Execution and Bug Tracking

Planned test cases are executed, and defects are logged and linked back to requirements for traceability. Test Management by Testsigma provides dashboards for real-time execution status and streamlines defect management.

6. Reporting

Comprehensive reports and dashboards are generated to track progress, quality, and defect trends. Teams can ensure exit criteria are met, summarize lessons learned, and formally close the testing cycle.

Why STLC over Traditional Methods of Software Testing?

Software Testing Life Cycle (STLC) is structured, systematic— and it helps in testing such that every nook and corner is covered. In turn it leads to the early detection of defects. This approach differs from the older ways where it paves way for better planning, collaboration between teams, and traceability with the end result being a high quality software that does not come at an excessive cost.

How Test Management by Testsigma is Helpful for STLC Implementation?

Test Management by Testsigma supports and enhances STLC in the following ways:

• Centralised Requirements to Test Case Traceability – Map requirements to test cases easily and track coverage.
• Collaborative Test Planning and Strategy – Assign roles, schedule tests, estimate effort, and align teams in one platform.
• Streamlined Test Case Creation and Versioning – Build, review, reuse, and maintain test cases/test suites with clarity and consistency.
• Environment & Lab Management – Track environments, configurations, versions required for tests; integrate with CI/CD where possible.
• Execution & Progress Monitoring – Run tests (manual or automated), log results, monitor pass/fail trends, visualize dashboards.
• Defect Management & Retesting – Link defects to test cases; manage retests; ensure closure criteria are met.

Comprehensive Reporting & Closure – Generate test-summary reports, metrics (coverage, test execution, defect density), lessons learned; verify exit criteria.

Possible Variations in the Standard STLC Process

There are circumstances where it is necessary to adjust the standard STLC process. Lеt’s еxplorе somе instancеs whеrе things don’t quitе follow thе еxpеctеd path.

Agile Development: In the Agile world, testing is not always aligned with the standard STLC sequence which is structured for Waterfall development. Agile values flexibility, quick feedback and continuous iteration; therefore testing often happens in parallel to development rather than following well-defined stages.

The planning, development and, execution of test cases can all overlap with development sprints leading to a more dynamic and iterative cycle. Clearly, the test does not follow traditional procedures; instead it flows together with development sprint.

Legacy Systems: STLC sequence may not be feasible due to technical constraints from outdated systems in organizations using legacy systems. Particularly, setting up the testing environment can be exceptionally challenging or impossible because these legacy systems may not be compatible with modern testing tools and techniques. Consequently, testing teams may need manual which calls for a different approach to the entire testing process.

Outsourced Testing: Thе tеsting procеss may not follow thе standard STLC sеquеncе whеn an organization outsourcеs its tеsting to a third-party vеndor. Typically, vеndors would havе thеir own tеsting mеthodologiеs and tools — which might not be aligned with what thе organization already has in placе. 

Continuous Tеsting: Within a DevOps setup, testing is integrated into the development process flow continuously. This involves running automated tests for every code modification or build without human intervention — aiming to identify defects and quality issues at their early stages within the development lifecycle. 

Continuous testing is all about breaking down the barriers between different testing phases. This means we need to come up with new ways to plan and implement tests. The testing team’s job is to create automated tests that can be easily reused and smoothly integrated into the development pipeline.

Summary

Quality software is important for the business as well as for the users. And STLC in testing ensures that every application you deploy is free of bugs and ready for users. STLC is a series of steps for testers to follow to begin the testing and complete the project on time with minimum issues.There are multiple advantages to STLC and why it is important in testing. There are primarily 6 phases in STLC that govern the testing process and determine the quality of the application. We have discussed all the steps above.One of the best ways to execute the STLC method is to adopt test automation where it is possible to remove redundancies and reuse the test cases. Automating the testing further helps record the results and accurately locate the issues in the applications.For all your automation testing needs, give Testsigma a chance. It is a no-code, AI-powered, cloud-based test automation that supports web, mobile, and API testing. Book a free demo now to see the tool in action.

Frequently Asked Questions