Mastering STLC: A Deep Dive

Testsigma Inc.
6 min readMay 31


Software Testing Life Cycle (STLC) is the overall process of testing a software application to ensure it meets the requirements and is of high quality. The cycle involves multiple stages: planning, analysis, design, execution, and closure. The team performs test case creation, execution, defect logging, and reporting at each stage. The STLC life cycle helps to identify and fix defects quickly and efficiently. Its goal is to produce a quality product that meets customer expectations.

Characteristics of STLC

As you know, STLC stands for ‘Software Testing Life Cycle.’ It is the process of testing a software application systematically. Here are the characteristics of STLC

  1. STLC life cycle is a systematic approach to ensure the quality of software products.
  2. STLC defines and implements a series of activities carried out in a specific order to ensure the quality of the software product.
  3. It includes planning, requirements analysis, design, implementation, testing, deployment, and maintenance.
  4. It ensures that software meets quality standards and user requirements.
  5. STLC involves both manual and automated testing methods.
  6. It includes functional, non-functional, and regression testing.
  7. Identifying and tracking defects until they are resolved is also part of the process.
  8. STLC is an ongoing process that continues throughout the development cycle of a software application.

Benefits of Software Testing Life Cycle (STLC)

  1. STLC in software testing organizes and manages activities through a systematic process.
  2. STLC in software testing process defines the scope and objectives, ensuring that it tests all aspects of the software.
  3. Produces all deliverables of the software testing process in a timely and effective manner.
  4. STLC helps identify potential issues and risks associated with the software early in the software development life cycle.
  5. It ensures the software meets the quality standards and customer requirements before the release.

STLC Phases

Each phase of the STLC model is essential for completing the software testing process. It comprises several stages, each with its objectives and deliverables. Let’s go through the details below:

Requirement Analysis:

Software testers work closely with the client during the requirement analysis phase to define the project’s scope, objectives, and expected outcomes. They review and analyze the requirements document to identify gaps or inconsistencies. They also perform a risk analysis to determine the potential impact of any missing or inaccurate requirements on the project’s success. Once the requirements are thoroughly analyzed and documented, the testing team can proceed with the development of test cases and test plans.

For example, for the purpose of this article, we will take the example of testing the Testsigma blog page. The URL is:, and the requirement is that the featured blog should appear with a larger thumbnail on the blog page and should appear at the top.

In the requirement analysis phase, the testers will analyse this requirement and try to understand what it means and how it could impact the existing product.

The image shows Create Requirements Phase

Test Planning:

After analyzing the project requirements and understanding the end-users needs, a test plan must be created. It must be flexible enough to accommodate changes that may arise during the testing process. The plan should include test scenarios and cases covering all functional and non-functional software requirements.

Continuing with our example above, the testing team would create a test plan, that would include the test cases for execution and a plan of how the test cases would be executed.

For example, few test cases would be:

1. The featured blog should appear on the top.

2. The featured blog should appear with a larger thumbnail.

3. The featured blog should be updated when an update is done on the backend.

4. Once the featured blog starts appearing on the blog page, rest of the blogs should appear below it as they appear now.

Above would be added to a Test Plan, the test plan would have the details about where the test cases would be executed and when. What would be entry criteria and the exit criteria.

Test Design:

In the Test design phase, we create a set of inputs, expected outputs, and preconditions for a given software module or component. It aims to reduce the risk of software defects, ensure compliance with requirements, and provide confidence in the quality of the software being tested.

Continuing with our example, in this phase the test cases would be filled in. As in — the test steps, the expected outcome and any other needed information.

Test Environment Setup:

The Test Environment setup is that phase where the environment is made ready for test execution. What test environments will be setup usually depends on the team and the organization. Some teams may have 1, some 2 and some may have more.

Continuing with our example, lets say the Testsigma team decided to test on staging, so they will make sure the staging environment is setup and ready for test execution.

Test Execution:

In this step, we can identify and report defects, which can be fixed before the software is released into production.

Continuing with our example, in this stage, the test cases created will be executed on the prepared test environment.

Test Closure:

During the test closure phase, the testing team prepares the final test report, which includes all the details related to the testing process, test outcomes, and any issues or defects identified during the testing phase. The report also summarizes the overall performance of the testing process, highlighting the areas that require improvement and the successful ones.

For our example, here, all the bugs found during testing will be reported in this stage.

Test Automation

In this stage, the test cases for automation are selected and automated.

There are many tools available in the market that let you automate your different types of test cases. For example, Testsigma for automating your test cases for web, mobile, APIs, and desktop applications from the same place. Selenium for automating your web applications. Appium for automating your mobile applications. JMeter for automating your performance tests.

What are Entry and Exit Criteria in STLC?

Entry Criteria: During the software testing life cycle planning phase, the team establishes entry criteria that must be met before beginning the software testing process. These criteria should include the following conditions:

  • Receipt of the requirements document
  • Receipt of the source code
  • Completed design document
  • Completed unit, integration, and system tests
  • Clearance of bug backlog
  • Clearance of the risk assessment

Exit Criteria: During the software testing life cycle planning phase, the team establishes the exit criteria that define the conditions for completing a software testing process. These criteria should enclose the following:

  • Verification of all test cases
  • Verification of all requirements
  • No outstanding bugs
  • No new bugs discovered
  • Changes not needed to the requirements
  • No changes to the design
  • All test coverage goals have been met
  • A software system is stable and performs as expected

Difference between STLC vs. SDLC

The Software Testing Life Cycle (STLC) is an essential component of the Software Development Life Cycle (SDLC). Despite their shared characteristics, significant divergences are outlined below in tabular form.

Wrap up

To wrap up, now you know Software Testing Life Cycle (STLC) is an important process for any software development. STLC provides a set of activities that help ensure the software’s quality. The STLC process helps ensure the software is reliable and meets customer requirements. It is also beneficial in identifying potential problems before they become critical and costly.

Overall, STLC is a wide process that helps ensure the software’s quality. Software developers must understand the process and activities to deliver a reliable, high-quality product.



Testsigma Inc.

Testsigma is a completely cloud-based codeless test automation tool that lets you create stable and reliable tests for web, mobile & APIs — all from one place.