Requirements analysis pptx

Requirements analysis 2 Contents  Software Development Life Cycle (SDLC)  Software Development stage  Requirements  Testing and requirements  Learn to think like a tester  Some examples  Writing test requirements 3 Software Development Life Cycle (SDLC) 4 Software Development Life Cycle (SDLC)  SDLC is a disciplined and systematic approach that divides the software development process into various phases, such as requirement, design, and coding  The phase-wise software development process helps you track schedule, cost, and quality of the software projects 5 Software Development Life Cycle (SDLC)  There are six phases of SDLC:  Feasibility analysis phase includes the analysis of project requirement.  Requirement analysis and specification phase includes gathering, analyzing, validating, and specifying requirements.  Design phase includes translation of requirements specified in the SRS into a logical structure that can be implemented in a programming language.  Coding phase includes implementation of design specified in the design document into executable programming language code.  Testing phase includes detection of errors in the software.  Maintenance phase includes implementation of changes and new requirements in the software at the customer location. 6 SDLC models  Are a tailored form of SDLC phases.  Provide a basis for categorizing and controlling the various activities required to develop and maintain the software system  Typical types of SDLC models are  Linear model  Iterative model 7 Linear Models  Linear models are suitable for projects where all the requirements are identified and well understood before the design of the software begins.  The two types of linear models are:  Waterfall model  Prototyping model 8 Waterfall model  Describes the software development process in a linear sequential flow.  Defines the software development process in seven phases:  Conception  Initiation  Analysis  Design  Construction  Integration and testing  Implementation and maintenance 9 Waterfall model 10 Prototyping model  Is a sample implementation of the system that shows limited and main functional capabilities of the proposed system.  Helps the customer determine how the features will function in the final software. [...]... a program Installability Portability 33 Contents Testing and requirements Learn to think like a tester 34 Testing Requirements     Usually done by review Are they complete? Are they reasonable? Can they be tested? 35 Requirements Testing     Testing of the requirements Determine all testable requirements Determine all non-testable requirements Write and execute the tests 36 ...    Project/Product Planning Requirements and Design Coding and Documentation Testing and fixing bugs Maintenance and Enhancement 23 Why Projects are Cancelled Project Impaired Factors % of Responses 1 Incomplete Requirements 13.1% 2 Lack of User Involvement 12.4% 3 Lack of Resources 10.6% 4 Unrealistic Expectations 9.9% 5 Lack of Executive Support 9.3% 6 Changing Requirements & Specifications 8.7%... Management Support 3 Clear Statement of Requirements 4 Proper Planning 5 Realistic Expectations 6 Smaller Project Milestones 7 Competent Staff 8 Ownership 9 Clear Vision & Objectives 10 Hard-Working, Focused Staff Other % of Responses 15.9% 13.9% 13.0% 9.6% 8.2% 7.7% 7.2% 5.3% 2.9% 2.4% 13.9% 26 Software Requirements  According to software engineering theory, software requirements should contain a finite... requirements should contain a finite list of behaviors and features, and each requirement should be written to be verifiable  Given a finite list of requirements and a set of completion criteria, requirements- based testing becomes a feasible process 27 Typical Requirements (FURPS)      Functionality – does it do what I need? Usability – is it easy to do what I need? Reliability – can it do what I need... the output of, a program “Intuitive” Human factors Consistency Documentation 30 Reliability Requirements     Frequency and severity of failure - MTBF Recoverability Predictability Accuracy 31 Performance Requirements      Speed Efficiency Resource consumption Throughput Response time 32 Supportability Requirements    Testability Adaptability Maintainability   Serviceability    Effort... Models     Requirements are in the hands of the testers early The project is better designed, with better focus Late changes to requirements or design are limited Test tasks of scheduling, planning, etc., are made easier 16 Advantages: Iterative Models     A shippable product is available early Progress (“Where are we?”) is much easier to track Many opportunities to reappraise requirements or... Supportability – what if is DOESN‟T do what I need? 28 Functionality Requirements  Correctness     Extent to which a program satisfies its specifications and meets customer expectations Features/Capabilities Generality Security  Extent to which access to software or data by unauthorized persons can be controlled 29 Usability Requirements  Ease of use      Measures the effort required to... Linear Models    Requirements must be well-reviewed early Test plan can be written early When System Testing does start, you are on the critical path 20 Effects on Testing: Iterative Models    Testing starts as soon as the first level of functionality is reached Test plan is written as you go Requests for design changes can be more easily made 21 Software Development stage Requirements 22 Software... Lack of IT Management 6.2% 10 Technology Illiteracy 4.3% Other 9.9% 24 Why Projects are Challenged Project Challenged Factors % of Responses 1 Lack of User Input 12.8% 2 Incomplete Requirements & Specifications 12.3% 3 Changing Requirements & Specifications 11.8% 4 Lack of Executive Support 7.5% 5 Technology Incompetence 7.0% 6 Lack of Resources 6.4% 7 Unrealistic Expectations 5.9% 8 Unclear Objectives... and the linear nature of the waterfall model Is ideal for developing software that are released in various versions The six phases of spiral model are:       Customer communication Planning Risk analysis Engineering Construction and release Customer evaluation 13 Spiral model 14 Component-Based Development Model  In a component-based development model:   Components are reused and combined with . Requirements analysis 2 Contents  Software Development Life Cycle (SDLC)  Software Development stage  Requirements  Testing and requirements  Learn to think. Feasibility analysis phase includes the analysis of project requirement.  Requirement analysis and specification phase includes gathering, analyzing, validating, and specifying requirements. . together 16 Advantages: Linear Models  Requirements are in the hands of the testers early  The project is better designed, with better focus  Late changes to requirements or design are limited 