So your team is preparing to launch a new software application. How do you ensure it works exactly as intended before unleashing it to customers? Rigorous testing is the key. While developers aim to code perfectly, creating complex software that accounts for every use case is nearly impossible. This is where the software testing life cycle comes in.
This post will explain what the software testing life cycle (STLC) is, provide a brief history of testing, outline its key phases, discuss integrating tests, and share best practices to deliver higher quality software.
What Exactly is the Software Testing Life Cycle?
The STLC offers a structured sequence of testing activities to evaluate and improve software quality systematically. It provides a framework to validate that each function works as expected according to specifications.
Think of it as a dynamic roadmap to methodically check if the software will perform well when real users start interacting with it in the wild. The goal is to identify defects and gaps as early as possible to fix them before launch.
Photo by Glenn Carstens-Peters on Unsplash
While tests are woven throughout development, treating it as a separate cycle enables rigorous validation by quality assurance (QA) specialists. This improves objectivity by moving testing upstream where it can steer projects toward meeting business intents versus just checking programmers‘ work.
When done right, testing early and often saves tremendous time and money compared to finding issues after launch. Industry data shows fixing bugs post-implementation is often 100x costlier. Reliability also builds customer trust. Simply put, the STLC helps catch problems customers otherwise would.
A Brief History of Software Testing Methodologies
In the early era of business computing back in the 1950s and 60s, testing was an informal debugging process done by programmers themselves. There were no dedicated testing phases or QA teams. As defense systems, financial applications, infrastructure came to rely more on software, defects led to catastrophic outcomes.
Formal testing roles and processes began emerging around the 1970s. However, testing still happened later rather than proactively guiding development. The 80s brought a shift from verifying code compliance toward validating requirements. This recognized testing’s importance for aligning software with business needs early.
The 1990s saw the creation of various structured testing methodologies like linear sequential modeling. Incremental iterative development also took hold – treating software as continually evolving rather than monolithic systems built in isolation. This promoted regular testing cycles from early stages.
By the 2000s, Agile further mainstreamed iterative test-driven development expediting feedback loops. Test automation also enabled executing higher test volumes faster to surface more defects sooner. Cutting silos further integrated testing across code, business logic and UI design daily.
Present day DevOps practices also demolished walls between functions. Developers now deploy to production themselves more frequently – making quality benchmarking every sprint critical. Data-driven decisions guide where to strengthen test reliability based on live monitoring. Testing is now an around the clock activity spanning the entire app lifecycle.
STLC Phases Explained
While variants exist, these major test phases provide broad coverage:
Requirements Analysis
Kicking off the STLC, this phase focuses on reviewing requirements needed to satisfy business objectives, user stories, compliance and regulatory needs among other formal specifications.
Key Activities:
- Review all documents conveying requirements – including functional, technical, operational aspects
- Interview business analysts, managers, customer proxies to clarify needs
- Define scope by identifying flows, use cases, screens, integrations in scope
- Determine test environment, tools, data prerequisites
- Assess requirements quality – are they testable with enough specifics?
- Develop prioritization guidelines of which areas need validating first
Exit Gates: Requirements approved, ensured testable. Environments acquisition underway.
Also Known As: Test basis analysis
Test Planning
With requirements understood, formal test planning begins. The specifics of testing strategy get defined here promoting alignment.
Key Activities:
- Identify types of testing – unit, integration, system, user acceptance, performance etc
- Develop schedule estimates through the multiple test cycles likely needed
- Detail test design approaches whether requirement, risk or use case-based
- Calculate human, data, tools resource needs
- Define metrics and reporting requirements
- Assign tester roles and responsibilities
Exit Gates: Test plan approved with detailed framework.
Also Known As: Test strategy.
Test Case Development
With a game plan in hand, concrete test cases are written to validate requirements get met.
Key Activities:
- Catalog conditions representing various paths – positive, negative, extreme
- Script manual test case steps + preconditions in detail
- Auto-code automated script logic flows
- Build test data input combinations to fuel test execution
- Review tests to ensure full requirements coverage
- Prioritize test cases so highest risk validate first
Exit Gates: Reviewed test cases ready for execution.
Also Known As: Test design.
Environment Setup
The tools, simulated components, data, configurations and end user devices enabling flawless test execution get set up.
Key Activities:
- Install tools for test management, requirements mapping, defect logging
- Create virtual services mimicking external systems
- Generate test databases with wide-ranging schema and volumes
- Provision diverse browsers, devices, OS combinations
- Ensure tools integrated end-to-end before testing begins
Exit Gates: Signed off integrated test management environment
Also Known As: Test bed creation
Test Execution
The most recognizable sequence – running tests against the evolving system and analyzing results. Done iteratively in multiple cycles.
Key Activities:
- Reset test environments before new test cycles
- Run manual test cases, log results as pass/fail/blocked
- Execute automated scripts in batches
- Record inputs, steps, and observed outcomes in detail
- Log defects when unexpected results surface
- Re-run to confirm fixes and expected behavior
Exit Gates: All critical test cases executed per plan. Acceptable defect levels achieved.
Also Known As: Test run
Test Closure
Wrap up testing with final reporting, retrospectives and transferring knowledge to ongoing production support teams
Key Activities:
- Document summary for stakeholders on scope, approach, execution, defects found
- Run metrics analysis on defects slipped through, test cases failed etc
- Archive test data, cases for future regression testing
- Conduct process improvement workshop capturing lessons learned
- Transfer app functional knowledge gathered during testing cycles to BA/DevOps teams
Exit Gates: Retrospective done, findings documented
Also Known As: Test completion
While sequential, previous phases often iterate several times or revisit as code or design changes. Optimizing the STLC remains key to smoothing this coordinated workflow between test and development.
Integrating Testing into the Software Development Life Cycle
The STLC represents the testing workflow within the broader software development life cycle (SDLC). During the SDLC, client needs get translated into technical specs, built and continuously improved via development teamwork.
Requirements analysis traditionally happened only after design. Modern agile practices changed that. Testers now collaborate alongside BAs continuously clarifying user stories. This validation role prevents lock-in to specifications not feasible or missing customer wishes.
Test planning also helps project manage the parallel dev and QA tracks unfolding. Code sprints deliver features matching upcoming test scenarios. Environments get integrated just-in-time as new components get added.
developers focus on component behavior – optimizing flows and defects found during CI test automation. Testers manually check broader end user journeys spanning integrated components. Feedback from both plus live production monitoring gives a comprehensive view for continuous improvement.
This integrated STLC approach amplified by DevOps culture is key to lowering risks and responding better to market dynamics today.
Software Testing Roles and Responsibilities
Delivering testing excellence relies on specialists fulfilling key roles:
Business Analysts frame requirements balancing user needs with business goals. Clarifying acceptance criteria focusing testing on what matters most.
Test Leaders define testing strategy and standards. They architect frameworks securing test coverage and reporting. Mentoring testing team execution while providing status visibility to executives.
Test Engineers develop concrete test cases to exercise application paths. They execute extensive trials and log any defects uncovered. Technical mastery to script automation also lies with them.
Test Data Analysts create, mask and manage the vast data sets fueling test execution at scale. Understanding edge cases and validating handling all formats.
DevOps Engineers enable collaboration through tools integration. Rapid provisioning of production-like environments and data also facilitates real-world testing.
Software Developers fix defects raised during testing cycles quickly. Writing testable code and reviewing tests gives them second hand coverage. Component focus here complements integration view testers bring.
While titles vary, these mutually reinforcing perspectives together catch more gaps pre-release.
Types of Testing
Not all test techniques serve the same purpose. Each addresses different aspects:
Unit Testing – Developers test isolated components like functions automatically during coding sprints. Confirms lowest code building blocks work first.
Integration Testing – Verifies interfaces between integrated components by QA after units test okay. Steps through modern UI, API and database layers end-to-end.
System Testing – Testers simulate production level volumes and ecosystems. Full workflows get put through operational readiness rigor at scale.
Acceptance Testing – Business analysts conduct final tests focused on only conformance to requirements per business intent. This user acceptance testing ensures solution solves the original asks.
Regression Testing – Confirming major new features or configuration changes do not impact prior working functionality through selective test reruns.
There are further specialties like localization, security, performance testing evaluating quality attributes like languages, firewall rules and response times. Optimizing which types to emphasize is part of test strategy.
Software Testing Best Practices
Beyond the sequence of STLC steps, applying testing wisdom accelerates defect detection:
Requirements Traceability – Linking every specified functional element to corresponding checks prevents gaps or gold plating beyond scope. These bidirectional traces between test cases and specs confirm fit. they also help assess change impact analysis when unstable specs continue shifting.
Shift Testing Left – Involving testers earlier to help analyze requirements prevents false starts down blind alleys. Constant collaboration between testers and business analysts reduces disconnects. Reviews of developer y unit test code quality also influences better foundation upstream.
Automate Regression Testing – Automating integration and system test cases enables conveniently re-running 1000s of checks daily. This allows bugs caught via automation to never regress while freeing up precious human tester timefocus on new scenarios and judgment-oriented interactions.
Prioritize Risks – Complex workflows, newer modules, intricate decision steps all represent high risk areas likely hiding undiscovered defects. Targeting manual testing to validate these first provides faster mitigation wins.
Require Defect SLAs – Enforcing a service level agreement for fixing severity one defects within 24 hrs motivates keeping up with testing velocity. Developers supporting test cycles through quick reliable defect resolution streamlines overall feedback.
Test Earlier and More Often – Bringing testing forward from just UAT at the end is game-changing. Hitting issues earlier reduces late big bang chaos and low code quality carrying forward. Testing a feature as soon its done lets issues get fixed immediately reducing cumulative debt.
There are many more – from test data tips to role definitions. But these high return practices catalyze testing contribute the most business value through the STLC.
Photo by Austin Distel on Unsplash
Key Takeaways
- The software testing life cycle offers a blueprint to evaluate applications methodically against specifications through requirements, planning, test case design, environment setup, execution and closure stages.
- Testing practices have their origins from an informal role to today‘s specialized integrated teams collaborating throughout the software development life cycle – preventing defects via early feedback.
- Understanding testing scope, types, roles and metrics-driven process refinements all contribute to releasing higher quality software faster by fixing defects sooner rather than later.
- Treating the STLC phases not as a one-time waterfall effort but iterative embedded practices improves outcomes.
- Optimizing not just individual testing competencies but cross-team dynamic collaboration and STLC visibility will achieve testing excellence over time.
The STLC provides an adaptive standards-based process for interdisciplinary quality assurance. Tailoring its mix of dialog driven requirements analysis, automated execution, manual spot inspections, tool integrations to each team’s development cadence results in launching reliably. Testing early prevents surprises later!
