Quality Assurance, Quality Control, and Testing - The Basics of Software Quality Management

When you buy a pear, at first glance, a pear may seem perfect, its shape, size, and color all look right. But only when you take that first bite do you know whether it’s truly good. It might taste sour or even have a worm inside. The same applies to products, digital or physical.

A website might look polished at first but begin revealing flaws once you scroll, navigate deeper, or attempt an action. Unlike a sour pear, though, defective software can have serious consequences. A faulty EHR system may jeopardize patient safety. An unreliable autopilot in a self-driving car could be life-threatening. Even minor website glitches can translate to massive revenue losses.

In this blog, we’ll share insights into software quality assurance, control, testing practices, and methodologies used to ensure excellence in digital products.

Software Quality Assurance vs. Quality Control vs. Testing

Human error is inevitable, but in software, the cost of mistakes can be catastrophic. Consider software bugs that led to billions in damages or failures like Starbucks’ register glitch or the F-35 fighter jet's radar malfunction.

To counteract such risks, the term software quality was brought forth — that of a product's capability to satisfy both explicitly stated and tacitly implied requirements under defined conditions.

Three most important aspects of quality management are quality assurance (QA), quality control (QC), and software testing. Though they all target the same aim — a quality product — they have different scope and orientation.

What is Quality Assurance?

QA focuses on the overall process of building a product. As described on the Google Testing Blog, it’s about “continuous and consistent improvement and maintenance of processes” to ensure the final product meets user needs.

QA activities include:

• Establishing quality standards and procedures
• Crafting guidelines for development teams
• Measuring progress
• Reviewing workflows for improvements

It involves both internal and external stakeholders, from developers to business analysts, and ultimately builds a framework to deliver consistent quality.

What is Quality Control?

QC ensures that a final product meets the standards set by QA. According to Investopedia, it's the process of maintaining or improving quality by identifying and correcting errors in the final product.

QC focuses on the end product through inspections, code reviews, and testing — all carried out before release.

What is Software Testing?

Testing identifies and helps resolve technical issues, often performed alongside or after development. It assesses code quality, performance, usability, security, and more.

Think of QA as ensuring the factory runs properly, QC as inspecting finished cars, and testing as taking each vehicle through performance and crash tests.

In this article, we’ll primarily explore software testing as the most hands-on and debated area of software quality.

Software Testing Principles

Over the past four decades, professionals have developed seven core principles of software testing that guide best practices:

• Testing reveals defects: Testing uncovers errors, but it can’t prove their total absence. The goal is to minimize undetected bugs, not claim perfection.
• Exhaustive testing is unfeasible: It’s impossible to test every input or scenario. For instance, ten fields with three input options each yield over 59,000 combinations. Instead, focus on likely scenarios.
• Early testing saves costs: Errors are cheaper to fix when found early. Testing should begin as soon as code is written, ideally from the planning stage.
• Defect clustering: Most issues are found in a small subset of components. If you spot errors in one area, check it more thoroughly.
• Pesticide paradox: Running the same tests won’t catch new bugs. Test cases need regular updates to stay effective.
• Context matters: Not all testing is equal. A fintech app demands high security, while a marketing site may prioritize performance and UX.
• No errors ≠ product success: Even if a product is bug-free, it may still fail if it doesn't meet real user needs.

Additional testing principles sometimes cited include:

• Independence of testing
• Testing for invalid inputs
• Using fixed test versions
• Clear documentation of expected outcomes

Still, the original seven remain the foundation of modern testing.

When Testing Happens in the Software Development Life Cycle

Testing can occur at different points in the SDLC depending on the methodology used.

Waterfall Model

In this traditional model, testing happens after development is complete. While thorough, this late stage testing often makes bug fixes costly and time-consuming.

Fixing issues earlier, during requirements or design, is cheaper and less disruptive. Once embedded in development, errors can compromise the product and lead to reputational and financial damage.

Agile Testing

Agile divides up development into sprints or iterations so that testing can be done concurrently with development. This "test early, test often" methodology is cheap and effective.

Feedback loops between stakeholders, developers, and testers ensure quick turnaround of issues and better-informed decisions.

DevOps Testing

DevOps builds on Agile by combining development, testing, and operations. DevOps emphasizes continuous integration, delivery, testing, and deployment - all backed by automation.

DevOps testers need to be coding-savvy and CI/CD tool-aware to survive in this high-speed environment. Based on the 2023 State of Testing survey, 91% of organizations use Agile, 50% use DevOps, and Waterfall remains active in 23%.

Software Testing Life Cycle

The Software Testing Life Cycle (STLC) outlines a structured process followed within or alongside the SDLC. It typically includes six phases:

Requirement Analysis

QA teams examine specifications, engage with stakeholders, and assess test priorities. They also determine which aspects can be automated and develop a Requirement Traceability Matrix (RTM), a checklist mapping requirements to test cases.

Test Planning

Like any formal process, software testing starts with thorough planning. The objective is to make sure that all stakeholders are aware of the customer's objectives, the fundamental functionality of the product, possible risks, and desired results. One of the most important documents at this point is the test mission or assignment, which aligns testing activities with overall project goals and coordinates activities within the team.

Test Strategy

Also known as a test approach or test architecture, the test strategy outlines the major tasks and potential challenges in a testing project. James Bach, creator of the Rapid Software Testing course, describes it as a product-specific, practical roadmap that helps teams clarify priorities.

Software engineer and author Roger S. Pressman also notes that a solid test strategy maps out testing phases, timing, and resource requirements.

Test strategies can be:

• Preventive: Created early in the SDLC.
• Reactive: Developed based on feedback or discovered issues during testing.

Common strategy types include:

Analytical Strategy: Based on requirements or risk analysis. QA teams collaborate with stakeholders to prioritize critical areas. While you can’t eliminate all risks, you can reduce them significantly.

Model-Based Strategy: Follows a predefined model (e.g., user journeys, data flows) to visualize expected behavior and assist with test automation. Best for complex systems but may be excessive for simpler apps.

Methodical Strategy: Uses pre-established checklists and standard procedures, often for security or regulatory testing.

Standard-Compliant Strategy: Ensures the software meets legal or industry standards (e.g., PCI DSS for payment systems), protecting the product and organization from compliance issues.

Dynamic Strategy: Involves informal testing methods like ad hoc or exploratory testing. It’s flexible and reactive, ideal when addressing bugs on the fly.

Consultative Strategy: Relies on input from domain experts or users to shape testing priorities. Useful for specialized applications or enhancement efforts.

Regression-Averse Strategy: Emphasizes automation to catch bugs after software updates. Reusable test cases validate both routine and exceptional scenarios before each release.

Test Plan

Though the test strategy has a bird's eye view, the test plan drills down to specifics, detailing who, when, what, and how they are going to execute the tests. The test plan changes with the project's lifecycle and gets revised by the project manager.

According to IEEE standards, a complete test plan should include:

• Test plan ID
• Introduction
• References
• Items to be tested
• Items not to be tested
• Pass/fail criteria
• Test approach (types, levels, techniques)
• Suspension/resumption conditions
• Deliverables (e.g., test scripts, reports)
• Testing environment
• Estimates and schedule
• Staffing/training needs
• Roles/responsibilities
• Risks and dependencies
• Approval requirements

Because drafting such a detailed plan is time-intensive, especially in Agile environments where speed is essential, James Whittaker proposed the 10 Minute Test Plan approach. The concept: strip down the process to essentials using lists and tables. While no team finished in 10 minutes, most completed 80% of the task in just 30 — far quicker than expected.

Test Case Development

Once planning is complete, QA professionals begin drafting test cases — detailed guides for evaluating specific product features. These include setup conditions, input data, actions, and expected outcomes. Once finalized, test cases are reviewed and linked to the Requirement Traceability Matrix (RTM) to ensure complete test coverage.

The aim is to create concise, easy-to-follow instructions that help ensure each function works correctly under specified conditions.

Test Environment Setup

Before running test cases, a secure, isolated environment that mirrors the production setup is prepared. This test environment includes the necessary hardware, software, data, and network settings tailored for testing.

Multiple environments may be used depending on the test type — unit testing, security testing, or system testing. Staging environments mimic real-world conditions closely and are often used for end-to-end testing with real data (without customer exposure).

Test Execution

With the environment ready, QA engineers begin executing test cases. Any bugs discovered are logged, fixed by developers, and retested. Test execution may go through several cycles before stability is achieved.

Deliverables from this phase include:

• Bug reports
• Execution summaries
• Test coverage reports
• Updated RTM with results

Test Closure

No software is ever 100% flawless. But testing reaches its formal conclusion when exit criteria are met. These may include:

• Completion of all planned test cases
• No critical defects remaining
• Stable performance with new features
• Compatibility across supported platforms/browsers
• Completion of User Acceptance Testing (UAT)

After closure, a summary report is delivered to stakeholders. Teams also conduct a retrospective to document lessons learned and refine processes for future projects.

Testing Concepts and Categories

Software testing can take many forms depending on when it occurs, what it checks, and how it’s performed. Understanding these distinctions is key to building a comprehensive QA process.

Static Testing vs. Dynamic Testing

Testing falls into two primary categories:

Static Testing: Involves examining code and documents without executing the software. This verification phase includes:

• Code Reviews – peer evaluations of code quality.
• Walkthroughs – informal sessions where developers explain code to colleagues.
• Inspections – formal analysis to ensure compliance with standards.

Dynamic Testing: Conducted during execution to validate software behavior. It involves different levels, types, and techniques (which we’ll explore next).

Levels of Software Testing

Testing levels vary based on what’s being tested, from individual units to the complete system.

Unit Testing: Focuses on individual components like functions or methods. Developers typically write and automate these tests early in development.

Integration Testing: Ensures that components or systems work well together. It can follow either:

• Bottom-up (start small, build up)
• Top-down (start big, refine)

System Testing: Validates the complete, integrated application. It checks for alignment with both functional and non-functional requirements. This is done in a staging environment by professional testers.

Acceptance Testing (UAT): Verifies whether the software meets user needs. It may include:

• Alpha Testing – by internal teams in a simulated environment.
• Beta Testing – by select customers in real-world settings.
• Gamma Testing – focused evaluations near release, often skipped due to constraints.

In Agile, these levels are applied repeatedly during feature rollouts — starting with units and expanding to integrated system and user validation.

Quality Testing Methods and Techniques

Different methods dictate how testing is performed:

• Black Box Testing: Tests inputs and outputs without knowing internal code. Ideal for UAT and system testing. Techniques include:
• Use Case Testing: Simulates real-world user behavior to detect functional flaws.
• White Box Testing: Focuses on internal logic and code structure. Conducted by developers, it aims to uncover hidden bugs and security gaps.
• Gray Box Testing: A hybrid method where the tester has partial knowledge of the code. It evaluates both functionality and system logic, often used in integration testing.
• Smoke Testing: A quick white-box check to verify if new builds are stable enough for further testing.
• Ad Hoc Testing: Informal, unscripted testing where the tester relies on experience and intuition. Useful early in development but should be supplemented with structured tests.
• Exploratory Testing: In Cem Kaner's definition, this technique motivates testers to learn, design, and carry out tests spontaneously while exploring the software. It is intuitive, quick, and gives immediate feedback about actual user experience.

Types of Software Testing

Depending on its objective, software testing is divided into several types. According to JetBrains’ State of Developer Ecosystem Survey 2023, these are the most widely used:

Functional Testing

Functional testing evaluates whether a system behaves according to its specified requirements. It focuses on output accuracy given defined inputs. The typical steps include:

• Identifying the intended functions
• Preparing input based on specifications
• Predicting expected output
• Running test cases
• Comparing actual results to expected ones

This black-box method is commonly applied at the system and user acceptance testing stages, with the emphasis on results rather than internal code logic.

Performance Testing

Performance testing measures a system’s speed, responsiveness, and stability under various loads. It consists of different subtypes:

• Load Testing – evaluates behavior under steadily increasing demand
• Stress Testing – tests performance at or beyond expected load limits
• Endurance (Soak) Testing – checks stability over extended periods of high usage
• Spike Testing – observes response to sudden load surges

Performance testing should begin early and continue throughout the development cycle to catch and fix bottlenecks before they become costly.

Regression Testing

This type checks whether changes to the software, such as updates or new features, have unintentionally broken existing functionality. It’s used to ensure that prior code still works as expected after modifications.

Regression testing combines white-box and black-box methods and is vital at integration and system testing levels. It often leverages reusable test scripts for efficiency.

Usability Testing

Usability testing looks at how easy and intuitive an application is to use. While User Acceptance Testing (UAT) tests functionality from a business point of view, usability testing is concerned with user perception and simplicity of use.

It can be performed as early as the design phase using product prototypes and ideally continues through the development lifecycle with feedback from various user groups.

Security Testing

Security testing identifies vulnerabilities that could lead to data breaches, unauthorized access, or system failures. Key techniques include:

• Penetration Testing (Ethical Hacking)
• Application Security Testing (AST)
• API Security Testing
• Configuration Scanning
• Security Audits

Security testing starts during requirement analysis and continues across all development stages and testing levels. It’s critical in safeguarding compliance and reputation.

Test Automation

Test automation plays a central role in continuous testing. It reduces manual effort, speeds up execution, and enhances coverage, key benefits in Agile and DevOps environments.

Steps in Test Automation:

• Initial project analysis
• Framework design
• Test case creation
• Implementation and execution
• Ongoing framework maintenance

Benefits of Test Automation:

Automation can be used across most test types and levels. It offers faster execution (up to 10x compared to manual), reduces human error, and increases test coverage to over 90% of the codebase.

According to the 2023 Software Testing and Quality Report by TestRail:

• Only 40% of testing is automated on average
• Automation adoption has grown steadily from 35% in 2020
• Open-source tools like Selenium, Cypress, JUnit, TestNG, and Appium are the most widely used

While automation is gaining traction, 39% of organizations cite automation development as their biggest challenge. Still, expanding automation remains a top priority - especially for regression, UI, end-to-end, integration, and mobile testing.

The best testing strategies combine manual and automated efforts to maximize efficiency and adaptability.

Quality Assurance Specialist

A QA specialist is a professional involved in ensuring software quality. In smaller teams, one person might handle everything from process setup to test execution. In larger organizations, these tasks are distributed among specialized roles:

• Software Test Engineer (STE): Focuses on manual testing, writing test cases, logging bugs, and validating software against requirements.
• Test Analyst: Works on understanding business needs, defining test requirements, and maintaining documentation like test plans and coverage reports.
• QA Automation Engineer: Writes test scripts, sets up automated environments, and integrates tests into CI/CD pipelines. Requires programming knowledge.
• QA Engineer: Has a broader scope than STEs, suggesting improvements, performing root cause analysis, and contributing to process refinement.
• Software Development Engineer in Test (SDET): Merges developer and QA skills. SDETs build test automation frameworks, review source code, and improve code quality.
• Test Architect: A senior-level expert responsible for test infrastructure, high-level strategy, and selecting tech stacks. Typically found in large enterprises.

Software Testing Trends

As technology evolves, software testing adapts to meet new demands. Key emerging areas include:

Security

Security is now a central part of IT strategy, as outlined in the World Quality Report. Vulnerabilities can lead to data breaches, reputation loss, and regulatory violations.

Security testing, especially in cloud environments, involves:

• Network security
• System software security
• Client-side application security
• Server-side application security

Security testing should be integrated into every phase of development and is typically conducted via white-box methods.

Artificial Intelligence and Generative AI

AI in testing is still emerging, but tools are increasingly capable of predictive analysis, cognitive automation, and self-healing test systems.

Startups like Mabl are leading the way by combining ML with functional testing. Mabl reduces manual input by observing workflows and automatically adapting to UI changes, broken links, or performance issues.

Generative AI can further enhance testing by:

• Detecting defects early
• Creating synthetic test data
• Automating test case generation

Studies show GenAI can reduce bug rates by 40% and cut test development time by 30–40%.

Big Data

As data volumes surge, traditional testing methods fall short. Big Data Testing validates the quality, consistency, accuracy, and completeness of data systems.

This involves:

• Data ingestion testing
• Data processing validation
• Database testing using tools like Hadoop, Hive, Pig, and Oozie

Big data testing ensures business logic operates correctly at scale and across massive datasets.

Conclusion

In 2012, Knight Capital lost $460 million in 45 minutes after deploying untested code to production, a fatal mistake that led to its collapse. Sadly, it’s not an isolated case. Many high-profile software failures stem from poor or overlooked testing.

Despite misconceptions, QA is far more than bug detection. It plays a pivotal role in shaping a product’s success, helping reduce risk, improve performance, and align development with user needs.

Experienced QA specialists don’t just test - they advise, guide, and enhance value delivery. With proper testing, companies can reduce long-term costs, speed up time-to-market, and build products their users can truly rely on.