PVK-HT061 Contents Introduction Requirements Engineering Project Management Software Design Detailed Design and Coding Quality Assurance Maintenance

PVK-HT062 Quality Assurance Introduction Testing oTesting Phases and Approaches oBlack-box Testing oWhite-box Testing oSystem Testing

PVK-HT063 What is Quality Assurance? Constructive vs analytic approaches to QA Qualitative vs quantitative quality standards Measurement oDerive qualitative factors from measurable quantitative factors Software Metrics QA is the set of the activities necessary to ensure the fulfillment of predefined quality standards.

PVK-HT064 Fault vs Failure ?! human errorfaultfailure can lead to Different types of faults Different identification techniques Different testing techniques Fault prevention and -detection strategies should be based on expected fault profile

PVK-HT065 Specification/ requirements Environment/ support Documen- tation OtherDesignCode Fault origin: WHERE? Missing Unclear Wrong Changed Better way Fault mode: WHY? Fault type: WHAT? Requirements or specifications Functionality HW interface SW interface User interface Functional description Test HW Test SW Integration SW Development tools Logic Computation Data handling Module interface/ implementation Standards (Inter-)Process communications Data definition Module design Logic description Error checking Standards HP´s Fault Classification

PVK-HT066 Fault Profile of a HP Division See [Pfleeger 98].

PVK-HT067 Testing Phases Unit test Unit test Unit test Integration test Function test Performance test Acceptance ( ,  ) test Installation test Component code Tested component Integrated modules Functioning system Verified software Accepted, validated system SYSTEM IN USE! Design specifications System functional requirements Other software requirements Customer requirements specification User environment System test Pre-implementation test

PVK-HT068 Pre-Implementation Testing Inspections Walkthrough oIn teams oExamine source code/detailed design Reviews oMore informal oOften done by document owners Advantages oEffective oHigh learning effect oDistributing system knowledge Disadvantages o Expensive

PVK-HT069 Software inspections These involve people examining the source representation with the aim of discovering anomalies and defects. Inspections not require execution of a system so may be used before implementation. They may be applied to any representation of the system (requirements, design,configuration data, test data, etc.). They have been shown to be an effective technique for discovering program errors.

PVK-HT0610 Integration Testing How to integrate & test the system Top-down Bottom-up Critical units first Functionality-oriented (threads) Implications of build order Top-down => stubs; more thorough top-level Bottom-up => drivers; more thorough bottom- level Critical => stubs & drivers. A DCB GFE Test E Test F Test G Test B,E,F Test C Test D,G Test all

PVK-HT0611 Verification: "Are we building the product right”. The software should conform to its specification. Validation: "Are we building the right product”. The software should do what the user really requires. Verification vs validation

PVK-HT0612 Testing Principles Construction of test suites oPlan tests under the assumption to find errors oTry typical and untypical inputs oBuild classes of inputs and choose representatives of each class Carrying out tests oTesters  implementers oDefine the expected results before running a test oCheck for superfluous computation oCheck test results thoroughly oDocument test thoroughly Simplify test oDivide programs in separately testable units oDevelop programs test friendly Each test must be reproducible

PVK-HT0613 Testing Tools / Support Debuggers oManual code instrumentation oInspect/trace variables o... Test data generators oInput: Program + testing strategy oOutput: Sets of input data Test-stub/-driver generators oSimulate client or server components, which are not yet available ClientServer