Software Testing Fundamentals

Software Testing Fundamentals

• Software testing involves analyzing a software item to find differences between existing and required conditions, known as bugs
• Testing serves to evaluate the software's features

Defining "Right" in Testing

• Standards or specifications are needed to measure or identify correct vs. incorrect results, requiring defined terms like:
  • Mistake
  • Fault/Defect
  • Failure
  • Error
  • Specification

Economics of Software Testing

• Software Development includes costs associated with testing programs
• Quality is most important for safety or mission-critical software like aviation software
• The goal of testing is to find as many defects as possible with minimal testing

Basics of Software Testing

• Software testing is a planned process to evaluate software quality by running it under controlled conditions
• Validation ensures the software performs the intended functions correctly
• Verification ensures the software conforms to requirements and design specifications

Key Testing Concepts

• Test Case constitutes a set of inputs, execution conditions, and expected results
• Test Suite is the collection of test cases
• Defects refer to any deviation from the expected result
• Failure is the observable incorrect behavior of the software
• Error refers to human mistakes in code or design that lead to defects

Common Issues in Testing

• Incompleteness occurs when tests do not cover all functionalities
• Time Constraints can force early releases without thorough testing of the software
• Defect Clustering indicates a small number of modules often contain most defects, following the Pareto Principle
• Pesticide Paradox occurs when repeated use of the same test cases stops finding new defects
• Testing Exhaustiveness is impossible, making prioritization a key aspect

Testing Techniques

• Static Testing means examining code without executing the program; e.g., reviews, inspections
• Dynamic Testing involves executing the code and comparing outputs to expected results
• Manual Testing is performed by humans
• Automated Testing uses tools/scripts to execute test cases

Software Testing Lifecycle

• Requirement Analysis means understanding what features need testing and identifying testable/non-testable requirements
• Test Planning encompasses defining objectives, resources, and schedules
  • Determining test types (functional, non-functional, etc.)
  • Risk analysis and mitigation strategies
• Test Case Development involves designing detailed test cases with steps, input, and expected output, as well as creating test data
• Test Environment Setup requires preparing hardware, software, network, and tools for test execution, and defining access/configurations
• Test Execution is executing test cases, logging results, and reporting defects
  • Retesting after fixes (regression testing)
• Test Closure requires evaluating test completion criteria
  • Documenting findings, lessons learned, and improvement suggestions
  • Archiving test artifacts for future reference

Testing Scopes

• Unit Testing involves testing individual functions or modules
  • It is usually automated and performed by developers
  • Focus is on functionality and error handling
• Integration Testing involves testing interactions between integrated modules
  • It ensures data flows correctly between components
  • Includes Top-down, bottom-up, sandwich (hybrid), and big bang types
• System Testing tests the entire system as a whole
  • It verifies functionality, performance, security, and usability
• Acceptance Testing ensures the software meets business requirements and is ready for production
  • Includes User Acceptance Testing (UAT) and Operational Acceptance Testing (OAT)

Testing Approaches

• Black-Box Testing tests without knowledge of internal workings
  • Focus on input-output behavior
  • Techniques include equivalence partitioning, boundary value analysis, and decision tables
• White-Box Testing tests internal logic and code structure
  • Techniques: Statement coverage, branch coverage, path coverage
• Gray-Box Testing is a combination of black-box and white-box testing
  • It utilizes testers with partial knowledge of the system's internals
  • Suitable for web applications and integrated systems