Software Development Practices and Methodologies. Svetlin . Nakov. Telerik . Academy. academy.telerik.com. http://codecourse.telerik.com. Table of Contents. Software engineering overview. Requirements. ID: 406645
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Practical Software Engineering Fundamentals
Software Development Practices and Methodologies
Table of Contents
Software engineering overviewRequirementsDesignConstructionTestingProject managementDevelopment methodologies overviewThe waterfall development processHeavyweight methodologiesAgile methodologies, SCRUM and XPSlide3
Requirements, Design, Construction, TestingSlide4
What is Software Engineering?
Software engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software.
Definition by IEEESlide5
Software engineering is:An engineering discipline that provides knowledge, tools, and methods for:Defining software requirementsPerforming software designSoftware constructionSoftware testingSoftware maintenance tasksSoftware project managementSlide6
Software Development Activities
Software development always includes the following activities (to some extent):Requirements analysisDesignConstructionTesting (sometimes)These activities do not follow strictly one after another (depends on the methodology)!Often overlap and interact
Software Project ManagementSlide7
Functional & Non-functionalRequirements, SRS, User Story CardsSlide8
Software requirements define the functionality of the systemAnswer the question "what?", not "how?"Define constraints on the systemTwo kinds of requirementsFunctional requirementsNon-functional requirementsSlide9
starts from a vision about the system
Customers don't know what they need!
Requirements come roughly and are specified and extended iteratively
outcome is the
Software Requirements Specification (SRS
or set of
is often used, especially for the user interface (UI
Software Requirements Specification (SRS)
The Software Requirements Specification (SRS) is a formal requirements documentIt describes in details:Functional requirementsBusiness processesActors and use-casesNon-functional requirementsE.g. performance, scalability, constraints, etc.Slide11
Agile Requirementsand User Stories
Requirements specifications are too heavyDoes not work well in dynamic projects that change their requirements every dayAgile development needs agile requirementsSplit into small iterationsHow to split the requirements?Use simple, informal requirements descriptionUser story: a small feature that brings some value to the end-user
What is User Story?
User storyUser needs to accomplish somethingWritten informal (in words / images / sketches)Looks like use-case but is different (less formal)User stories haveActor (who?)Goal (what?, why?)Other infoOwner, estimate, …
User Story – Example
It is always hard to describe and document the requirements in comprehensive
Good requirements save time and money
during the project!
requirements reduces the changes
Prototypes significantly reduce
Agile methodologies are flexible to changes
Incremental development in small iterationsSlide15
Software Requirements Specifications (SRS), User Stories and UI Prototypes
Software Architecture and Software DesignSlide17
Software Architecture and Software Design
Software design is a technical description (blueprints) about how the system will implement the requirementsThe system architecture describes:How the system will be decomposed into subsystems (modules)Responsibilities of each moduleInteraction between the modulesPlatforms and technologiesSlide18
System ArchitectureDiagram – ExampleSlide19
Software Architecture Diagram – Example
Describes the internal module structure
Interfaces, data design, process design
Describes the classes, their responsibilities, relationships, dependencies, and interactions
Internal Class Design
responsibilities, algorithms and interactions between themSlide21
Software Design Document (SDD)
The Software Design Document (SDD)Formal description of the architecture and design of the systemIt contains:Architectural designModules and their interaction (diagram)For each moduleProcess design (diagrams)Data design (E/R diagram)Interfaces design (class diagram)Slide22
Implementation, Unit Testing, Debugging, IntegrationSlide24
During the software construction phase developers create the softwareSometimes called implementation phaseIt includes:Internal method designWriting the source codeWriting unit tests (optionally)Testing and debuggingIntegrationSlide25
Writing the Code
Coding is the process of writing the programming code (the source code)The code strictly follows the designDevelopers perform internal method designas part of codingThe source code is the output ofthe software construction processWritten by developersCan include unit testsSlide26
Testing the Code
Testing checks whether the developed software conforms to the requirementsAims to identify defects (bugs)Developers test the code after writing itAt least run it to see the resultsUnit testing works betterUnits tests can be repeated many timesSystem testing is done by the QA engineersUnit testing is done by developersSlide27
Debugging aims to find the source of already identified defect and to fix itPerformed by developersSteps in debugging:Find the defect in the codeIdentify the source of the problemIdentify the exact place in the code causing itFix the defectTest to check if the fix is working correctlySlide28
Integration is putting all pieces togetherCompile, run and deploy the modules as a single systemTest to identify defectsIntegration strategiesBig bang, top-down and bottom-upContinuous integrationSlide29
Coding != Software Engineering
Inexperienced developers consider coding the core of development
In most projects coding is only
% of the project activities!
The important decisions are taken during the requirements analysis and design
Documentation, testing, integration, maintenance, etc. are often disparaged
Software engineering is not just coding!
Software Verification and TestingSlide31
What is software verification?It checks whether the developed software conforms to the requirementsPerformed by the Software Quality Assurance Engineers (QA engineers)Two approaches:Formal reviews and inspectionsDifferent kinds of testingCannot certify absence of defects!Can only decrease their ratesSlide32
checks whether the developed software conforms to the requirements
Testing aims to find defects (bugs)
Unit tests, integration tests, system tests, acceptance tests
Stress tests, load tests, regression tests
Tester engineers can use automated test tools
to record and execute testsSlide33
Software Testing Process
Test planningEstablish test strategy and test planDuring requirements and design phasesTest developmentTest procedures, test scenarios, test cases, test scriptsTest executionTest reportingRetesting the defectsSlide34
Test Plan and Test Cases
is a formal document that describes how tests will be performed
List of test activities to be performed to ensure meeting the requirements
Features to be tested, testing approach, schedule, acceptance criteria
Test scenarios and test cases
– stories to be tested
– tests of single functionSlide35
Test Plans and Test Cases
Software Project ManagementSlide37
What is Project Management?
Project management is the discipline of organizing and managing work and resources in order to successfully complete a projectSuccessfully means within defined scope, quality, time and cost constraintsProject constraints:
What is Software Project Management?
Software project management
Management discipline about planning, monitoring and controlling software projects
Identify the scope, estimate the work involved, and create a project schedule
Project monitoring and control
Keep the team up to date on the project's progress and
What is Project Plan?
is a document that describes how the work on the project will be organized
Contains tasks, resources, schedule, milestones, etc.
Tasks have start, end, assigned resources (team members), % complete, dependencies, nested tasks,
Project management tools simplify creating and monitoring project plansSlide40
Project Plan – ExampleSlide41
Waterfall, Scrum, Lean Development, Kanban, Extreme ProgrammingSlide42
What is a Development Methodology?
is a set of practices and procedures for
organizing the software development process
A set of rules that developers have to follow
A set of conventions the organization decides to follow
A systematical, engineering approach for organizing
and managing software
Back in historyThe "Waterfall" ProcessOld-fashioned, not used todayRational Unified Process (RUP)Microsoft Solutions Framework (MSF)Modern development methodologiesAgile development processesScrum, Kanban, Lean Development, Extreme Programming (XP), etc.
The Waterfall Development ProcessSlide45
The Waterfall Process
The waterfall development process:
Formal methodologies are heavyweight!
UI Design Document
Full of documents,
The Agile Manifesto
“Our highest priority is to satisfy the customer through early and continuousdelivery of valuable software“
Manifesto for AgileSlide49
The Agile Spirit
IncrementalWorking software over comprehensive documentationCooperationCustomer collaboration over contract negotiationStraightforwardIndividuals and interactions over processes and toolsAdaptiveResponding to change over following a plan
ScrumKanbanLean Software DevelopmenteXtreme Programming (XP)Feature-Driven Development (FDD)Crystal family of methodologiesAdaptive Software Development (ASD)Dynamic System Development Model (DSDM)Agile Unified Process (AUP)Slide51
Extreme Programming:The 12 Key Practices
The Planning GameSmall ReleasesMetaphorSimple DesignTest-Driven DevelopmentRefactoringPair ProgrammingCollective OwnershipContinuous Integration40-Hour WorkweekOn-site CustomerCoding StandardsSlide52
Scrum is an iterative incremental framework for managing complex projectsScrum roles:Scrum Master – maintains the Scrum processesProduct Owner – represents the stakeholders Team – a group of about 7 peopleThe team does the actual development: analysis, design, implementation, testing, etc.
SprintAn iteration in the Scrum developmentUsually few weeksProduct BacklogAll features that have to be developedSprint BacklogAll features planned for the current sprint
The Scrum Process Framework
Sprint Planning MeetingAt the beginning of the sprint cycleEstablish the Sprint backlogDaily Scrum stand-up meetingEach day during the sprint – project status from each team memberTimeboxed to 15 minutesSprint Review MeetingReview the work completed / not completed
Software Engineering Fundamentals
You are assigned to develop a simple Web-based software for conversion between different units, e.g. inches to meters, EUR to USD, radians to degrees, …Define the software requirements for the project as user stories (3-4 user story cards).Create a UI prototype for the software.Create a simple SDD for the software (1 page).Create a simple test plan for the software (describe 5-6 test cases).Create a project plan for the software (1 page).