Software Quality Assurance Overview

Software Quality Assurance and Testing

• Software quality assurance is a critical activity for any business producing products used by others.
• It's a planned, systematic activity, not a spontaneous event.
• It needs to be integrated into the development process for software.
• Continuous improvement is the overall goal of software quality assurance.

Software Quality Assurance Outline

• Quality Assurance is an umbrella activity.
• Software standards are essential for quality assurance.
• Product quality is assessed using design quality metrics and program quality metrics.
• Project quality is assessed through reviews and software configuration management (SCM).
• ISO 9001/9000-3 and SEI Capability Maturity Model (CMM) are standards for process quality.

The Four P's in Software Development

• Software quality is achieved through the combined effort of people, process, and product.
• People: education and training of software engineers.
• Process: project management and monitoring.
• Product: testing and measurement.

Software Quality Assurance (SQA)

• SQA involves procedures, techniques, and tools used by professionals to ensure software products meet or exceed specified standards throughout development.
• SQA is essential in any business that creates products for others.
• SQA must be planned and systematic.
• SQA should be built into the development process.
• Continuous improvement is a driving force in SQA.

SQA - An Umbrella Activity

• SQA comprises methods, tools, standards, procedures, metrics, and formal technical reviews.
• The activities of testing, and software configuration management (SCM) are crucial parts of SQA to meet or exceed quality standards. A quality system of software engineering depends on each practice, each of them are part of the whole practice system.

Why SQA Activities Pay Off

• The cost of fixing defects is much lower early in development.
• Requirements phase defects are inexpensive to fix, but if they can be fixed in the design, code, test, system testing, and field use it will be more expensive.
• SQA focuses on preventing defects early in the development process by increasing the cost to fix a defect over time.

Software Quality

• Software quality is not just about meeting specifications; other attributes like safety, security, reliability, resilience, robustness, understandability, testability, adaptability, modularity, complexity, portability, usability, reusability, efficiency, and learnability also matter.

Principles of Software Quality Assurance

• Establish standards and quality attributes for software.
• Measure software quality to determine conformance to standards.
• Track quality attributes to assess progress.
• Use quality information to improve future software.

Software Standards

• Software standards encapsulate best practices to avoid mistakes.
• They provide a framework for implementing SQA.
• They ensure continuity and reduce learning effort in new projects.
• Product standards define characteristics of software artifacts for quality.
• Process standards define how the software process should be conducted.
• Deciding which standards to ignore, use as is, modify, or create is a vital part of every project.

Software Metrics

• Metrics measure aspects of software systems, processes, or related artifacts, including control metrics (planning, managing, and controlling the development process) and predictor metrics (predicting product qualities like ease of maintenance).
• External attributes are discovered post-release use; internal attributes are measurable from the software.

Product Quality: Design Quality Metrics

• Design quality focuses on how easily a component (e.g. module) is maintainable.
• Cohesion, coupling, understandability, and adaptability are key aspects of design quality.
• Understanding complexity is key to evaluating and improving design quality.
• Maintainability is essential for long-term maintenance, modification, and improvement efforts.
• Both structural and informational fan-in/fan-out metrics are useful in assessing the complexity and resulting maintainability of components.
• IEEE Standard 982.1-1988 provides metrics for design quality indexes like DSQI to assess design quality, using the measure results and history results.

Product Quality: Program Quality Metrics

• Halstead's Software Science measures the complexity and effort involved based on operators and operands in a component.
• McCabe's Cyclomatic Complexity analyzes the control flow (logic) of program components to gauge testing and debugging difficulty.

Product Quality: Formal Approaches

• Proving program correctness involves logically validating that requirements are transformed correctly.
• Statistical quality assurance focuses on identifying and fixing the most prevalent causes of defects (80-20 Rule).
• The Cleanroom Process is a formal approach combining both proving and statistical methods to improve software quality.

Project Quality: Reviews

• Reviews are an essential part of software project quality validation.
• Early reviews help prevent defects.
• Types of reviews include requirements walkthroughs, analysis walkthroughs, design walkthroughs, code walkthroughs, and test plan reviews.
• Formal technical reviews can pinpoint up to 75% of defects.

Software Configuration Management (SCM)

• SCM is a vital activity to control and track changes, plans, specifications, programs, documents, and data throughout a project life cycle.
• SCM involves identifying, controlling, and tracking configuration items.

Controlling Configuration Items: Baselines

• Establishing baselines marks a point where all changes must be formally tracked and documented.
• Items are checked out and in to ensure change is tracked in every step.
• Before an item is finalized, it must pass a formal review.

Controlling Configuration Items: Version Control

• Version control tracks the evolving changes to configuration items.
• This process ensures modifications are handled in a controlled and traceable way.

SCM Change Control

• Change requests from users are evaluated and either approved or disapproved.
• SCM procedures ensure a documented and controlled process exists for all changed configuration items.

SCM Audit and Status Reporting

• Audits verify that changes are implemented correctly.
• Status reporting helps keep all parties informed about the status of change.

SCM Support

• SCM employs a library to store, label, identify, and track the status of configuration items across different versions.

SCM Benefits

• SCM reduces effort, enhances productivity, improves software integrity and security, increases quality, and builds better record-keeping and control.

Process Quality

• Unlike physical products, software quality depends on diverse factors.
• Software is designed not manufactured and has human skills, experience, business pressures, etc.
• Development processes are usually organization specific.
• Insufficient resources often negatively impact quality.

Process Quality: ISO 9001/9000-3

• This is a quality management framework that provides standardized procedures and supports improved quality control.
• The framework can be customized for a particular organization. Certification is widely seen as a marketing tool, not only for actual quality improvements. 

Process Quality: The SEI Capability Maturity Model (CMM)

• CMM is a framework of five incremental levels for software process improvement.
• These levels range from ad hoc initial processes (Level 1) to optimizing processes (Level 5), focusing on progressively more formalized, measurable, and robust best practices to continuously improve quality.

People Quality: The People Capability Maturity Model (PCMM)

• PCMM focuses on how effectively an organization manages its people to support improvement.
• It covers different levels with focus on skills, training, and increasing knowledge to improve development and business results.

SQA The Bottom Line

• SQA procedures need to be documented in quality manual.
• Each project needs a quality plan to identify priorities.
• Established standards are necessary for documentation and compliance monitoring.
• Reviews and metrics are crucial for quality assurance.

Summary- Software Quality

• Quality software is developed through mechanisms already built into the development process.
• Management support and well-defined policies and procedures are needed for quality development.
• Testing is an important aspect, but it's not the only factor in creating high-quality software.

Dive into the essential elements of Software Quality Assurance and Testing. This quiz covers key concepts such as the importance of systematic quality activities, standards like ISO 9001, and the roles of people, process, and product in achieving software quality. Test your understanding of how continuous improvement can be integrated into the development lifecycle.