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SDLC (Software Development Life Cycle)

Software Development Process Model

Nadeesha Thilakarathne

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Software Development Life CycleRequirement Gathering

& Analyzing

Design

Implementation& Coding

Testing

Deployment

Maintenance

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1. Requirement Gathering & Analyzing • Business requirements are gathered• Meetings with project managers & stake holders • Identify • “Who will use the system ”• “How the system should work “• “What should be the input & output of the system ”

• Analyze requirements for validity & incorporation of requirements • Finally prepare Requirement specification document

Requirement Specification INPUT

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2. Design • Prepare system & software design from software requirement

specification.• It helps in • Specifying hardware & system requirements• Defining overall system architecture

• Logical & Physical designing

Design Documentation INPUT

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3. Implementation / Coding • Work divide into modules • Actual coding started • Longest phase in SDLC

Implementation INPUT

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4. Testing • Tested against requirements• Detection of errors in the software • Test related activities• Test case generation • Testing criteria

• This phase complete• Unit testing• Integration testing • System testing• Acceptance testing Test Report INPUT

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Unit Testing • Smallest testable part of the application

• Function • Class• Procedure • Interface

• Use to make sure individual parts are working correctly• Done by developers • White box testing is used to execute unit testing • Done before integration testing

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White Box Testing (glass-box)• Known as structure – based testing• Test internal structures (as opposed to its functionality - black-box testing )• Advantages

• Easy to reveal hidden errors• Easy to automate

• Disadvantages • Expensive (Time & Money)• In some occasions not realistic • Missing functionality may not discover

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Integration Testing • Individual testing modules are combined and test as a group• Verify

• Functional • Performance • & reliability requirements placed on major design items

• These groups of units (design items) excised through their interfaces using black – box – testing

Integration Testing Unit Testing Validation Testing After Before

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Black Box Testing • Examine the functionality of an application • Not looking at the internal structure or working • Applicable levels of software testing

• Unit • Integration• System • Acceptance

• Aware of what the software is supposed to do ,not aware of how it does

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System Testing• Testing conduct on completed integrated system to check

• System's compliance with its specified requirements• Should required no knowledge in internal design or codes (Black – box –

testing )• System testing performed with FRS(Functional Requirement Specification) or

SRS (System Requirement Specification)

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Acceptance Testing • After the completion of system testing system will be delivered to the user or

customer for acceptance testing • Help to establish confidence on system

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5. Deployment • After the successful completion of testing process application will

deploy for the use of customer.

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6. Maintenance • Enhancing & optimizing deployed software

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Waterfall-ModelRequirements definition

System & software design

Implementation & unit testing

Integration & system testing

Operation & maintenance

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Waterfall-Model• First published model of the software development lifecycle• Principal stages of the model map onto fundamental development

activities

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Waterfall-Model• Requirements analysis and definition • Services, constrains & goals are established by consultation with system users

• System & software design • Partitions the requirements either hardware or software systems• Establish overall system architecture• Involves identifying & describing the fundamental software system

abstraction & their relationship

• Implementation & unit testing • Software design is realized as a set of programs or program units.

SOMMERVILLE –SOFTWARE ENGINEERING

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Waterfall-Model• Integration & unit testing • Integrated & tested as a complete system • Ensure that the software requirements have been met

• Operation & maintenance • Involves in correcting errors • Improving the implementation• Enhancing the system’s services as new requirements discovered

SOMMERVILLE –SOFTWARE ENGINEERING

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Agile Software Development• Biggest problem with software development is changing requirements• Agile processes accept the reality of change versus the hunt for

complete, rigid specifications

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Agile Software Development

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Agile Software Development• Advantages• Satisfy customer with rapid ,continuous delivery• Customers, developers & testers continuously interact with each other • Continuous attention • Late changes in requirements are welcome

• Disadvantages• Lack of emphasized on necessary designing & documentations • Difficult to assess the effort required at the beginning of the software

development life cycle.

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References• http://www.agile-process.org/• http://istqbexamcertification.com/what-is-agile-model-advantages-di

sadvantages-and-when-to-use-it/• https://en.wikipedia.org/wiki/Main_Page• Sommerville –software engineering

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Your Valuable Feedback is

always welcome…. Nadeesha