What is the Software Testing Life Cycle? STLC Phases Explained

Software testing is at the core of exceptional digital experiences. If you can’t sufficiently and thoroughly validate your products before customers use them, you risk alienating them. Software testing isn’t just a stage before release. It must be a multi-faceted, ongoing effort across the organization.

Just as there is a software development life cycle (SDLC) for developing digital products, there is a software testing life cycle (STLC) for validating them. Various team members participate in software testing processes at different stages. These efforts help businesses achieve their quality goals in a strategic, documented manner.

So, what is the software testing life cycle? We’ll provide an explanation of the software testing process, as well as the individual STLC phases and challenges.

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What is the software testing life cycle?

The software testing life cycle is a sequence of tasks designed to understand the state of a system and make recommendations for improvement. The tasks that define STLC phases typically reflect the perspectives of stakeholders across the business to ensure all needs are met. Just as the software testing process incorporates many stages and functions, the STLC involves strategizing, planning, executing and completing test cycles.

In the past, software testing processes occurred shortly before product release as a way to ensure digital products don’t contain defects. These bugs negatively affect core functionality and the user experience. However, as digital systems became more complex and businesses released batches of software and apps more often, the STLC evolved. When organizations delay the software testing process to the end of the development cycle, the result is costly bug fixes and release delays. Software testing no longer waits until a product is fully developed. 

Over the last couple of decades, some organizations have included STLC phases before and during development to maximize resources. Some of the following tactics spread the software testing process and responsibilities:

• test automation
• test-driven development
• crowdtesting
• shift-left testing
• shift-right testing

An effective STLC produces more comprehensive and valid results than a traditional post-development testing stage. Thus, these software testing processes help organizations make changes that ultimately drive customer satisfaction and higher revenue. Completing these STLC phases is not a pre-release burden. It’s an effort to discover key insights that will benefit the business over the short and long terms.

6 key STLC phases

The software testing life cycle provides confidence in a software release. The STLC delivers that confidence through a series of tasks that take validation through ideation to design and execution.

Each STLC phase is useful in its own way to achieve high-quality software releases. Likewise, each STLC phase comes with its own goals and deliverables, all intended to catch defects and optimize test coverage.

Let’s dig into these software testing life cycle (STLC) phases:

• Requirement analysis
• Test planning
• Test case design and development
• Test environment setup
• Test execution
• Test cycle closure

1. Requirement analysis

Most development initiatives begin with software requirements that specify what the business expects from the project. Software requirements often include high-level business needs, architectural requirements that detail how the feature will be designed and supported, and detailed system requirements from which developers build the product. System requirements include functional and non-functional specifications, both of which present opportunities to test and validate.

In this STLC phase, testers work both within their own teams and cross-functionally to contextualize how they will test the software. Requirement analysis often includes brainstorming sessions to identify blind spots. The team then prioritizes certain assessments to ensure all requirements are covered. Techniques like mind mapping to visualize relationships between requirements and root cause analysis to identify potential issues early occur in this STLC phase.

When in doubt or lacking requirements documentation, the QA team will question the engineering or business side. This helps clarify and solidify a testing strategy. Thus, software testing processes begin before a single test executes.

Common challenges in the requirements analysis phase of the STLC include:

• incomplete or ambiguous requirements, which can lead to misaligned expectations and testing goals
• difficulty in obtaining stakeholder buy-in, which can slow down the analysis process
• lack of documentation, making it hard for testers to establish clear objectives

2. Test planning

The second STLC phase guides much of the work to follow. Test planning takes the insights found during requirements or product analysis and turns them into a documented QA strategy.

The test team leadership determines what resources and efforts will evaluate the release. The resulting test plan documentation both informs testers and other departments how the testing work will begin. A good test plan often includes sections such as:

• risk analysis
• backup plans
• resource allocation
• test environment details
• criteria for success

This plan is especially helpful if other members of the organization will take part in testing and bug remediation, such as developers executing unit tests and writing hotfixes.

The plan spells out several details of the software testing processes to be undertaken. Test plan details often include the scope, objectives, types of functional and non-functional tests (both automated and manual), and details for the test environments. Once these details are determined, test management sets roles and timelines for the work. Finally, the testing team can determine what deliverables it will provide upon completion of the STLC phases.

Common test planning challenges in this part of the software testing process include:

• estimating the time and resources required, which can lead to timeline overruns
• defining the scope of testing, particularly in large projects where multiple components and integrations need coverage
• aligning test plans with constantly changing requirements, especially in Agile environments where requirements may evolve frequently
• balancing automated and manual testing resources to ensure optimal efficiency and coverage.

3. Test case design and development

With the test plan in place, testers can begin to write and create detailed test cases. In this STLC phase, the QA team fleshes out the details of the structured tests they will run, including any test data they will need to facilitate those tests. While tests must ultimately validate the areas defined by requirements, testers can apply their skills and creativity in how they achieve this task.

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Challenges in the test execution phase of the STLC include:

• managing flaky automated tests, which lead to unreliable results and complicate defect analysis
• ensuring sufficient test coverage within the time constraints, especially for complex or large-scale systems
• balancing manual and automated testing efforts to achieve efficient, yet comprehensive coverage
• effectively managing retesting and regression testing to confirm that bug fixes do not introduce new issues

6. Test cycle closure

The final STLC phase is test cycle closure. During this stage, the testing team provides a test closure report summarizing its findings. This report typically includes overviews of the testing work and results, an assessment of the testing, and the manager’s approval.

During the test cycle closure, the testing team checks its deliverables. Closure details relevant to the testing work include the test strategy, test case documents, automated test scripts and test results. The team will then complete and close incident reports, which detail unusual or unexpected behavior that the test team observes during testing. The team must also archive the resources it used during testing, such as scripts, tools and environments, for later use.

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From there, the organization plans the product for support and release, which often includes acceptance and feedback from customer representatives. Communication is key in this STLC phase, as additional perspectives might uncover a quality, cost, or coverage issue that the rest of the group missed. These discussions can yield additional analysis or inform how to improve QA work in the future. In this way, the software testing process never truly ends. Remember, it’s a cycle.

Test cycle closure challenges include:

• capturing and analyzing all relevant testing metrics to ensure process improvement
• coordinating feedback from multiple stakeholders to address quality gaps before release
• ensuring that all testing resources, such as scripts and environments, are properly archived for future use
• communicating lessons learned to prevent repeated issues in future cycles

Agile affects the software testing life cycle

The common software testing life cycle phases above follow a sequential approach similar to Waterfall application development. However, as many businesses rethink how they develop products, testing must also adapt to align with iterative organizational practices and pace of releases.

The QA team might follow an Agile testing method instead, which impacts the STLC phases above in various ways. For instance, Agile encourages continuous collaboration, iterative development and ongoing testing. That means that the traditional linear approach must be modified to support more fluid and overlapping STLC phases. This fluidity in the software testing process helps ensure faster feedback loops, earlier bug detection and alignment with evolving requirements. 

Additionally, Agile testing places an emphasis on shift-left and shift-right testing to reduce QA bottlenecks. While test automation is included in the STLC phases above, Agile testing might place a higher priority on methods like in-sprint testing and test-driven development, both of which generally result in cleaner, simpler bits of code. Production testing, or shift-right testing, helps the QA team identify defects after the test cycle closure. While these defects are often more costly to correct, it’s better late than never when it comes to fixing a bug. Shift-right often involves exploratory testing and user testing to find defects that test cases failed to uncover.

In short, the STLC phases above might change slightly depending on the organization’s development and testing philosophies.

Make your software testing life cycle more efficient

There’s no time to spare when it comes to testing. The pressure to meet tight release deadlines is higher than ever. QA teams must look for any edge throughout the software testing life cycle that helps them release a high-quality product quickly.

Applause can be there with you from the very outset of the project as a strategic testing partner, genuinely invested in your company’s success throughout these STLC phases. Applause provides world-class expertise and a worldwide community of testers to help you release exceptional products.

Incorporating Applause into the software testing process expands opportunities for diverse testing scenarios, including on a broader range of devices and in different locations, which lets you focus on what to test, not how you will do it. From the very beginning of the STLC, Applause can pose important strategic QA questions to inform manual or automated QA strategy.

We’re flexible to your needs. Applause works where and how you need us in all STLC phases. Once you determine testing priorities, we help you determine the scope and timelines of the testing — or simply work within the ones you define.

Whatever your software testing process needs are, Applause is ready to help facilitate a solution. Whether you need an enterprise-grade automation framework, manual testers in a specific market and with specific characteristics, or a partner to help facilitate shift-left testing, Applause is ready to deliver — and exceed — your testing goals.

Let’s chat about how we can make your software testing life cycle more efficient, now and in the future.

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