An Introduction to Software Testing Life Cycle (STLC): Definition and Phases.

The SeaLights Software Metrics Guide
for Better and Faster CI/CD

Request a Live Demo

Software Testing Life Cycle (STLC) is a testing strategy that can help you efficiently meet software quality standards. STLC enforces systematic testing, which is performed in phases. STLC is often confused with Software Development Life Cycle (SDLC), but while STLC is focused on testing, SDLC encompasses all development stages. Read on for an in-depth look at STLC and its six phases.

In this article you will learn:

What Is Software Testing Life Cycle?

Software Testing Life Cycle (STLC) is a process used to test software and ensure that quality standards are met. Tests are carried out systematically over several phases. During product development, phases of the STLC may be performed multiple times until a product is deemed suitable for release.

What Is the Role of Software Testing Life Cycle?

An STLC helps teams: 

  • Refine the agile testing process, increasing consistency and effectiveness
  • Clearly define goals and expectations for each project aspect
  • Apply time constraints to project testing
  • Ensure that each feature is tested and passing before additional features are added
  • Verify that project requirements are met

Some common activities included in a Software Testing Life Cycle framework are:

  • Analysis of client and stakeholder system requirements
  • Creation of a traceability matrix (a document that determines project completeness by comparing requirements with features) 
  • Identification of testing techniques and types needed for each feature
  • Prioritization of features to be targeted
  • Analysis of how tasks can be automated
  • Identification of environment information

Some advantage of STLC include:

  • Testing is shifted left in the development cycle. This ensures that tests are designed meaningfully and that feature specs are clear.
  • Systematic testing leads to a faster testing process and enables teams to uncover and address issues faster.
  • Project progress is easier to track since testing is performed with well-defined goals and phases.

STLC vs SDLC: How Do They Differ?

Although both are related to software development, with overlapping timelines, Software Development Life Cycle and Software Testing Life Cycle follow different goals and guidelines. STLC can be performed as a series of steps within the SDLC cycle or can be performed alongside SDLC phases. 

The primary difference is that SDLC is responsible for collecting requirements and creating features accordingly. Meanwhile, STLC is responsible for creating tests adapted to the collected requirements and for verifying that features meet those requirements. If the SDLC created features that do more than necessary, it’s often okay, however, if STLC tests do more than necessary an unnecessary burden is placed on the team. 

Both life cycles require the cooperation of stakeholders, DevOps, and testing teams. Without this cooperation, you cannot verify that requirements are properly defined, that tests are relevant, or that results are applied properly.

Source: Goodcore

The 6 STLC Phases In-Depth

Software Testing Life Cycle  consists of 6 phases, each with defined entry and exit criteria and associated activities and deliverables. Entry and exit criteria define when a phase can start and when it can end. Activities and deliverables define what actions are performed and what the expected result is. Some of these phases can be performed simultaneously while others require previous phases to be completed first.

Source: guru99

Phase 1: Requirement Analysis

During this phase, feature requirements collected in the SDLC process are evaluated to identify testable aspects. If necessary, testing teams may need to consult with stakeholders to clarify requirements. These requirements can either be functional or non-functional, defining what a feature can do or it’s characteristics respectively. The ability to automate testing is also evaluated during this phase.

  • Entry Criteria—documented requirements, acceptance criteria, and intended product architecture.
  • Exit Criteria—approved requirement traceability matrix (RTM) and automation feasibility report.

Phase 2: Test Planning

During this phase, the test strategy is outlined in a test plan document. This strategy includes tools needed, testing steps, and roles and responsibilities. Part of determining this strategy is a risk and cost analysis and an estimated timeline for testing.

  • Entry Criteria—requirement analysis, RTM, and automation feasibility report.
  • Exit Criteria—approved test plan including timelines and risk/cost analysis.

Phase 3: Test Case Development

During this phase, test cases are created. Each case defines test inputs, procedures, execution conditions, and anticipated results. Test cases should be transparent, efficient, and adaptable. Once all test cases are created, test coverage should be 100%. Any necessary automation scripts are also created during this phase.

  • Entry Criteria—approved test plan including timelines and risk/cost analysis.
  • Exit Criteria—approved test cases and automation scripts.

Phase 4: Test Environment Setup

During this phase, testing environments are configured and deployed. This phase may include a variety of testing tools, including TestComplete, Selenium, Appium, or Katalon Studio. Sometimes, this phase also includes setting up test servers. Once environments are deployed, smoke tests are performed to ensure that environments are working as expected with all intended functionality.

  • Entry Criteria: system design and project architecture definitions.
  • Exit Criteria: a fully functional test environment and approved test cases.

Phase 5: Test Execution

During this phase, features are tested in the deployed environment, using the established test cases. Expected test results are compared to actual and results are gathered to report back to development teams.

  • Entry Criteria—all exit criteria from previous steps.
  • Exit Criteria—all tests are performed and results are documented.

Phase 6: Test Cycle Closure

This is the last phase of the STLC, during which a test result report is prepared. This report should summarize the entire testing process and provide comparisons between expected results and actual. These comparisons include objectives met, time taken, total costs, test coverage, and any defects found.

  • Entry Criteria—test results and logging from all previous phases.
  • Exit Criteria—delivered and approved test closure report.

Design Productive Software Testing Life Cycles With Sealights Software Quality Intelligence

Software Testing Life Cycle is a process that can help you better organize your testing workflow, and drive efficiency into an otherwise chaotic process. There are many factors to consider during each phase, and different testing tooling requirements to consider. 

Planning is a crucial part of the process, but planning doesn’t have to be a time-consuming manual process. You can use Software Quality Intelligence solutions, like Sealights, to make data-driven decisions. To ensure maximum productivity, you should prioritize testing. You can do that with insights provided by Sealights Software Quality Intelligence.

Sealights analyzes your software, and then provides you with the feedback necessary to prioritize testing and build efficient testing cycles. With Sealights, you can discover which tests are needed to improve software quality, and which tests are redundant and should not be performed. 

For more advice on how to increase agile velocity and productivity with quality intelligence, learn more about Quality Intelligence.