Cap3 Agile Flashcards
Quali sono i metodi dell’agile e che caratteristiche hanno?
I metodi usati dall’agile:
- hanno il focus sul codice piuttosto che sulla progettazione
- hanno un approccio iterativo allo sviluppo software
- consegne rapide e evoluzioni rapide per rispondere ai cambiamenti dei requisiti
e sono:
**Customer involvement ** - Customers should be closely involved throughout the development process. Their role is provide and prioritize new system requirements and to evaluate the iterations of the system.
Incremental delivery - The software is developed in increments with the customer specifying the requirements to be included in each increment.
People not process -The skills of the development team should be recognized and exploited. Team members should be left to develop their own ways of working without prescriptive processes.
Embrace change - Expect the system requirements to change and so design the system to accommodate these changes.
Maintain simplicity - Focus on simplicity in both the software being developed and in the development process. Wherever possible, actively work to eliminate complexity from the system
In cosa consiste lo sviluppo agile?
Specifiche, progettazione e implementazione sono intervallate.
Il sistema viene sviluppato come una serie di versioni e incrementi.
Frequenti consegne di nuove versioni per valutazioni.
Esteso uso d strumenti di supporto come test automatici per aiutare lo sviluppo.
Documentazione minima, e focus sul codice.
In cosa consiste la tecnica agile dell’extreme programming (XP)?
Incremental planning - Requirements are recorded on story cards and the stories to be included in a release are determined by the time available and their relative priority. The developers break these stories into development ‘Tasks
Small releases - The minimal useful set of functionality that provides business value is developed first. Releases of the system are frequent and incrementally add functionality to the first release.
Simple design - Enough design is carried out to meet the current requirements and no more.
Test-first development - An automated unit test framework is used to write tests for a new piece of functionality before that functionality itself is implemented.
Refactoring - All developers are expected to refactor the code continuously as soon as possible code improvements are found. This keeps the code simple and maintainable.
Pair programming - Developers work in pairs, checking each other’s work and providing the support to always do a good job.
Collective ownership - The pairs of developers work on all areas of the system, so that no islands of expertise develop and all the developers take responsibility for all of the code. Anyone can change anything.
Continuous integration - As soon as the work on a task is complete, it is integrated into the whole system. After any such integration, all the unit tests in the system must pass.
Sustainable pace - Large amounts of overtime are not considered acceptable as the net effect is often to reduce code quality and medium term productivity
On-site customer - A representative of the end-user of the system (the customer) should be available full time for the use of the XP team. In an extreme programming process, the customer is a member of the development team and is responsible for bringing system requirements to the team for implementation.
In cosa consiste la tecnica agile dello User stories for requirements?
In XP, a customer or user is part of the XP team and is responsible for making decisions on requirements.
User requirements are expressed as user stories or scenarios.
These are written on cards and the development team break them down into implementation tasks. These tasks are the basis of schedule and cost estimates.
The customer chooses the stories for inclusion in the next release based on their priorities and the schedule estimates.
In cosa consiste la tecnica agile del refactoring?
Conventional wisdom in software engineering is to design for change. It is worth spending time and effort anticipating changes as this reduces costs later in the life cycle.
XP, however, maintains that this is not worthwhile as changes cannot be reliably anticipated.
Rather, it proposes constant code improvement (refactoring) to make changes easier when they have to be implemented.
Programming team look for possible software improvements and make these improvements even where there is no immediate need for them.
This improves the understandability of the software and so reduces the need for documentation.
Changes are easier to make because the code is well-structured and clear.
However, some changes requires architecture refactoring and this is much more expensive
Re-organization of a class hierarchy to remove duplicate code.
Tidying up and renaming attributes and methods to make them easier to understand.
The replacement of inline code with calls to methods that have been included in a program library.
In cosa consiste la tecnica agile del Test-first development?
Testing is central to XP and XP has developed an approach where the program is tested after every change has been made.
XP testing features:
Test-first development.
Incremental test development from scenarios.
User involvement in test development and validation.
Automated test harnesses are used to run all component tests each time that a new release is built.
Writing tests before code clarifies the requirements to be implemented.
Tests are written as programs rather than data so that they can be executed automatically. The test includes a check that it has executed correctly.
Usually relies on a testing framework such as Junit.
All previous and new tests are run automatically when new functionality is added, thus checking that the new functionality has not introduced errors.
In cosa consiste la tecnica agile del Customer involvement?
The role of the customer in the testing process is to help develop acceptance tests for the stories that are to be implemented in the next release of the system.
The customer who is part of the team writes tests as development proceeds. All new code is therefore validated to ensure that it is what the customer needs.
However, people adopting the customer role have limited time available and so cannot work full-time with the development team. They may feel that providing the requirements was enough of a contribution and so may be reluctant to get involved in the testing process.
In cosa consiste la tecnica agile del Test automation?
Test automation means that tests are written as executable components before the task is implemented
These testing components should be stand-alone, should simulate the submission of input to be tested and should check that the result meets the output specification. An automated test framework (e.g. Junit) is a system that makes it easy to write executable tests and submit a set of tests for execution.
As testing is automated, there is always a set of tests that can be quickly and easily executed
Whenever any functionality is added to the system, the tests can be run and problems that the new code has introduced can be caught immediately.
In cosa consiste la tecnica agile del Problems with test-first development?
Programmers prefer programming to testing and sometimes they take short cuts when writing tests. For example, they may write incomplete tests that do not check for all possible exceptions that may occur.
Some tests can be very difficult to write incrementally. For example, in a complex user interface, it is often difficult to write unit tests for the code that implements the ‘display logic’ and workflow between screens.
It difficult to judge the completeness of a set of tests. Although you may have a lot of system tests, your test set may not provide complete coverage.
In cosa consiste la tecnica agile del Pair programming?
Pair programming involves programmers working in pairs, developing code together.
This helps develop common ownership of code and spreads knowledge across the team.
It serves as an informal review process as each line of code is looked at by more than 1 person.
It encourages refactoring as the whole team can benefit from improving the system code.
In pair programming, programmers sit together at the same computer to develop the software.
Pairs are created dynamically so that all team members work with each other during the development process.
The sharing of knowledge that happens during pair programming is very important as it reduces the overall risks to a project when team members leave.
Pair programming is not necessarily inefficient and there is some evidence that suggests that a pair working together is more efficient than 2 programmers working separately.
Cos’è lo Scrum?
Scrum is an agile method that focuses on managing iterative development rather than specific agile practices.
There are three phases in Scrum.
The initial phase is an outline planning phase where you establish the general objectives for the project and design the software architecture.
This is followed by a series of sprint cycles, where each cycle develops an increment of the system.
The project closure phase wraps up the project, completes required documentation such as system help frames and user manuals and assesses the lessons learned from the project.
Cos’è il Product backlog?
This is a list of ‘to do’ items which the Scrum team must tackle. They may be feature definitions for the software, software requirements, user stories or descriptions of supplementary tasks that are needed, such as architecture definition or user documentation.
Cos’è lo ScrumMaster?
The ScrumMaster is responsible for ensuring that the Scrum process is followed and guides the team in the effective use of Scrum. He or she is responsible for interfacing with the rest of the company and for ensuring that the Scrum team is not diverted by outside interference. The Scrum developers are adamant that the ScrumMaster should not be thought of as a project manager. Others, however, may not always find it easy to see the difference.
Cos’è uno sprint?
A development iteration. Sprints are usually 2-4 weeks long.
