Software Testing and Quality Assurance

What is Quality and Why it's Important

• Quality is the degree of excellence of something
• In an IT product or service, quality is defined as "Meeting the requirements of the customer"
• Quality is important for customer satisfaction and to meet the required functionality with user-friendly features

Cost of Quality

• Cost of quality refers to "money spent beyond the cost of building the same product right the first time"
• Prevention cost, appraisal cost, internal failure cost, and external failure cost are the different types of cost of quality

Quality Attributes

• Correctness, reliability, efficiency, and maintainability are some of the quality attributes
• For example, in a medical system, correctness is essential to ensure error-free patient medical history

Verification and Validation

• Verification: "Did I make the product correctly?" (done at the starting of the development process)
• Validation: "Did I make the correct product?" (done at the end of the development process)
• Verification involves reviews, meetings, walk-throughs, and inspections to evaluate documents, plans, code, requirements, and specifications
• Validation involves testing to ensure the software system meets the required functions and attributes

Verification and Validation Planning

• 5 steps involved in planning:
  • Identify V&V scope
  • Establish specific objectives
  • Analyze project input
  • Select tools and techniques
  • Develop Software Verification and Validation Plan (SVVP)

Static Testing (Verification)

• Involves manual or automated reviews of documents
• Done during the initial phase of testing to catch defects early in STLC
• Examines work documents and provides review comments
• Work documents include requirement specifications, design document, source code, test plans, test cases, test scripts, help or user document, web page content

Dynamic Testing (Validation)

• Involves executing code to check functional behavior, memory/cpu usage, and overall performance
• Confirms that the software product works in conformance with business requirements
• Can be black or white box testing and is performed at all levels of testing

V&V Involvement in SDLC

• Requirements Phase: Determine test strategy, adequacy of requirements, and generate functional test conditions
• Design Phase: Determine consistency of design with requirements, adequacy of design, and generate structural and functional test conditions
• Program (Build) Phase: Determine consistency with design, adequacy of implementation, and generate structural and functional test conditions for modules and units
• Test Phase: Test application system
• Installation Phase: Place tested system into production
• Maintenance Phase: Modify and retest

V&V Involvement in SDLC (continued)

• Requirement gathering and analysis: Testing team starts Test Planning phase after requirements analysis is completed
• Design: Testers come up with Test strategy and mention what to test, how to test
• Implementation/Coding: Testing is done against requirements to ensure product meets needs addressed and gathered during requirements phase
• Deployment: Customer to beta testing, and any changes or bugs are reported to engineering team
• Maintenance: Modify and re-test

Requirement Validation and Review

• Walkthroughs, reviews, and inspections are techniques used to identify defects at each stage of the development and maintenance life cycle
• Key documentation includes review logs, check sheets, test strategy and test plan, test cases and test scripts, test results log, and defect logs

Risk

• Risk is an issue that can be avoided or mitigated
• Types of risks include schedule risk, budget risk, programmatic risks, operational risks, technical risks, and testing risks
• Risk analysis involves forming a risk analysis team, identifying risks, estimating the magnitude of risk, and selecting testing priorities
• Risk reduction methods include contingency planning