Untitled presentation

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Title: Software Quality Engineering

• Lecture 1

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Quality Exploration

• Let's start with a question: What is Quality?

• Where is Quality?

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Quality Car Identification

• Which one is a quality car?

• Example: Sofa 7194

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Definitions of Quality

• Transcendental View: Recognizable but not definable.

• User View: Fitness for purpose.

• Manufacturing View: Conformance to specification.

• Product View: Tied to inherent product characteristics.

• Value-Based View: Dependent on the payment a customer is willing to make.

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IEEE Definition of Quality

• Concise Definition: Quality is the degree to which a system, component, or process meets specified requirements, customer or user needs, or expectations (IEEE Standard Glossary of Software Engineering Terminology).

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Components of Quality

• Conformance to Requirements: Requirements must be clear; non-conformances are defects.

• Fitness for Use: Must meet customer expectations.

• Important Parameters:

  • Quality of Design: Determination of requirements.

  • Quality of Conformance: Adherence to stated requirements.

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Software Quality Expectations

• Two Key Expectations:

  • Do the Right Things: Software performs intended functions accurately.

  • Do Things Right: Software executes functions correctly and efficiently.

• Example: Airline Reservation System.

  • Doing Right: Should handle flight reservations, validated for purpose.

  • Doing Right: Should validate reservations quickly, avoiding errors.

• Focus Activities: Validation and Verification (ensure needs and operations are met).

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What is Software Quality Engineering

• The practice of integrating quality checks throughout the development cycle.

• Aim: Ensure efficient testing for quality during the software development cycle.

• Responsibility includes designing and maintaining quality assurance policies and processes.

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Interaction Question

• Reflecting on experiences in software development: What is the role of quality? How can quality engineering be performed?

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Software Quality Engineering Process

• Key Components:

  • Set quality goals early in development.

  • Choose and monitor QA strategies to meet those goals.

  • Analyze QA and development data for continuous improvement.

  • Feedback Loop: QA insights assist in better decisions and measurable improvements.

• Real-Life Scenario: Self-driving car.

  • Testing for traffic law adherence, inspection for logic errors, fault tolerance for sensor failures.

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Challenges in Software Quality

• Increased software complexity due to modern system demands.

• Quality issues can have severe impacts due to high reliance on software.

• Example: Banking app; incorrect interest calculations lead to loss of trust.

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Relationships in Software Quality

• Software Quality Engineering (SQE):

  • Overarching process ensuring high-quality software.

  • Scope: Encompasses all quality-related activities.

  • Goal: Achieve and maintain software quality.

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Quality Assurance (QA)

• Definition: A subset of SQE focused on systematic activities to prevent/reduce software problems.

• Scope: Techniques include inspection, defect prevention, fault tolerance, and testing.

• Role: To meet predefined quality standards by minimizing problem occurrence.

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Testing in Software Quality Engineering

• Definition: Core QA activity to verify software against specifications.

• Scope: Detects defects and validates system functionality.

• Role: Central QA method for identifying discrepancies and aiding defect removal.

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Overview of Relationships

• SQE serves as the framework for QA activity planning and management.

• QA is part of SQE employing technical and procedural methods.

• Testing plays a pivotal role in validation and defect detection within QA.

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Practical Example of SQE, QA, and Testing

• SQE: Establish quality goals (e.g., 99.9% uptime).

• QA: Code inspections, validation techniques, automated fault tolerance.

• Testing: Functional, stress, and regression tests across various scenarios.

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Importance of Software Quality

• Ubiquity: Software systems central to modern life (e.g., information processing).

• Dependence: Reliable, efficient software necessary for user activities.

• High-Quality Requirements: User-friendly and maintainable software essential.

• Developer Role: Developers must engage in quality assurance activities.

• Evidence-Based Quality: Quality claims must be backed by measurements.

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Lecture Summary

• Transition to Software Quality Engineering, Lecture 2.

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Objectives of SQA

• Process Goals:

  • Fit-for-use software production.

  • Implement and check compliance with suitable processes.

  • Evaluate processes for improvement.

  • Produce Correct, Reliable, Accurate, and Maintainable products.

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Reliability of Product

• Definition: Likely performance under specific conditions over time.

• Example: A washing machine functions without issues for 5 years.

• Software Reliability: Encompasses correctness, accuracy, consistency.

• Example: A banking app should correctly calculate transactions.

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Definition of Software Reliability

• Ability to perform defined functions under specified conditions.

• Reliance on correctness, confidence, accuracy, precision over time.

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What is Software Maintenance?

• Definition: Modifications post-delivery to correct faults and improve performance.

• Types of Maintenance:

  • Corrective: Fixes bugs post-delivery.

  • Adaptive: Updates to maintain operation with changing environments.

  • Perfective: Adds improvements or features.

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(Duplicate of Page 23)

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Software Process Improvement

• Definition: Planned enhancements to software creation process.

• Distinctions:

  • Process Improvement: Upgrades and standardizes software production.

  • Process Management: Effective resource usage for developing quality software.

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Achieving Objectives through Verification and Validation

• Verification: Ensures accuracy in building software (process adherence).

• Validation: Ensures the right software is built (meets user needs).

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Achieving Objectives through Testing and Evaluation

• Testing: Engaging software under conditions to check functionality and compliance.

• Evaluation: Judging overall software quality and performance based on testing.

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Establishing Software Quality Program

• Set requirements for software quality.

• Establish methodology for development processes.

• Evaluate process and product quality consistently.

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Phases of SDLC with SQA Activities

• Inception: Project conceptualization and feasibility.

• Requirements Analysis: Gathering and documenting software needs.

• SQA Activity: Requirements review for completeness.

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Phases of SDLC with SQA Activities (Design)

• High-Level Design: Structure outlines (e.g., modules).

• SQA Activity: Inspect the design for accuracy and issues.

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Phases of SDLC with SQA Activities (Coding and Testing)

• Coding: Writing code per design.

• SQA Activity: Conduct reviews and testing for error detection.

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Exercise Scenario

• Create a management system for class scheduling at an educational institution.

• Key requirements: Resource management and ease-of-use considerations.

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Requirement Specification

• Details of resource fields and constraints (e.g., uniqueness, alphanumeric types).

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Task Assignment

• Analyze requirements, raise concerns for improvement, and generate test cases.

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Classroom Manager Implementation

• Core functionalities for resource management and classroom setup.

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UI Testing Task

• Identify and report defects related to UI.

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Software Quality Engineering - Lecture 3

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Software Quality Framework

• Quality defined by various models (ISO-9126).

• Key characteristics of software quality.

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ISO-9126 Functionality

• Definition: Functionality attributes meeting user needs.

• Sub-characteristics include suitability, accuracy, interoperability, security.

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ISO-9126 Reliability

• Definition: Capability to maintain performance.

• Sub-characteristics include maturity, fault tolerance, and recoverability.

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ISO-9126 Usability

• Definition: Effort needed for use and user assessment.

• Sub-characteristics include understandability, learnability, and operability.

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ISO-9126 Efficiency

• Definition: Performance vs resource usage under conditions.

• Sub-characteristics include time behavior and resource behavior.

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ISO-9126 Maintainability

• Definition: Effort needed for modifications.

• Sub-characteristics include analyzability and changeability.

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ISO-9126 Portability

• Definition: Software adaptability to various environments.

• Sub-characteristics include adaptability and installability.

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Implementing ISO-9126 in SDLC

• Phase wise application of ISO-9126 in context of a fitness tracking app.

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Continuing Implementation of ISO-9126 in SDLC

• Ongoing focus on testing, deployment, and maintenance in app lifecycle.

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Understanding Software Defects

• Definitions: Error (human mistake), Fault (hidden problem), Failure (unexpected behavior).

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Dealing with Software Defects

• Defect Prevention: Steps to mitigate defect occurrence.

• Example: Clear requirement documentation and coding guidelines.

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Continued Defect Management

• Detection & Removal: Identify problems before release.

• Example: Testing and code reviews.

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Defect Containment Solutions

• Strategies to minimize impacts of existing defects.

• Example: Quick fixes and backup systems.

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Economics of Software Defects

• Analysis of defect costs through development phases.

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Defects Pattern Analysis

• Comparison of defect rates with and without QA functions.

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Cost to Fix Defects Over Time

• Cost implications of defects across different development phases.

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Transition to Lecture 4

Background

• Previous focus on correctness shifted to QA processes aimed at defect minimization.

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Overview of QA Approaches

• Focuses on prevention, detection and removal, containment methods.

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Defect Prevention Techniques

• Strategies to eliminate error sources to enhance software quality.

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Error Source Elimination

• Primary prevention methods including clarity in requirements and training.

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Error Blocking Techniques

• Code reviews and strict coding standards to enhance quality.

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Exercise Regarding Handling Errors

• Handling division by zero error effectively in code.

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Exercise Solution

• Corrected code handling division by zero with error messages.

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Techniques for Defect Reduction

• Inspections and software testing as core methods for quality assurance.

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Analyzing Software with Static and Dynamic Techniques

• Techniques for identifying faults without and during program execution.

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Strategies for Defect Containment

• Focus on maintaining functionality in the face of faults.

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Failure Containment Approaches

• Critical system safety measures for defect management.

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Definition of Software Testing

• Critical activity; verifying and validating software functionality.

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Types of Testing

• Different testing stages from unit to beta testing focusing on functionality.

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Testing Approaches

• Black-Box: Functional view; testing based on requirements.

• White-Box: Structural view; examining code.

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Comparing Testing Approaches

• Insight into black-box and white-box testing differences and contexts.

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Black-Box Testing Example

• Practical example of verifying functionality without accessing code.

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White-Box Testing Example

• Tailored testing utilizing program insights.

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When to Stop Testing

• Criteria based on coverage and reliability for efficient testing completion.

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Software Quality Engineering - Lecture 5

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Introduction to Software Testing

• Overview of purpose and significance in the development lifecycle.

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Role of Testing

• Critical for error prevention and ensuring customer expectations are met.

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Requirement Analysis in STLC

• Initial analysis ensures understanding and clarity of testing requirements.

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Exercise on Leave Module

• Engage with defining leave functionalities.

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Solution for Leave Module Requirements

• Functional and non-functional requirements documented.

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Test Case Documentation

• Comprehensive test cases to track testing activities.

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Test Planning Activities

• Essential steps for establishing effective test management.

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Test Planning Goals

• Ensuring well-defined goals and strategies for testing.

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Test Planning Entry/Exit Criteria

• Establishing necessary requirements for testing preparation and validation.

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Test Planning Group Collaboration

• Group tasks to develop a comprehensive test plan.

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Test Case Development Focus

• Key activities in creating structured test cases for execution.

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Test Case Development Criteria

• Comprehensive documentation and preparation details.

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Exercise on Test Case Development

• Steps directed at defining and organizing test cases.

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Test Case Development Solution

• Illustrative examples of test case creations and their expected results.

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Test Environment Setup

• Preparatory actions for ensuring a suitable testing environment.

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Environment Setup Criteria

• Requirements needed for confirming environment readiness.

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Test Execution Overview

• Core activities during the execution phase of testing.

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Execution Criteria

• Entry and exit points for effective test execution.

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Test Execution Steps

• Structured guide for conducting and tracking testing outcomes.

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Bug Report Template Example

• Detailed formats for documenting discovered defects.

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Test Closure Phase Overview

• Summary activities marking the conclusion of the testing cycle.

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Closure Criteria

• Essential conditions for completing the testing phase.

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Test Closure Steps

• Systematic approach for finalizing the testing process.

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Test Closure Reporting Example

• Sample reporting depicting test outcomes and recommendations.