Extreme Programming Modified : Embrace Requirements Engineering Practices

Extreme Programming ModifiedExtreme Programming Modified::Embrace Requirements Engineering PracticesEmbrace Requirements Engineering Practices

J. Nawrocki, M. Jasinski, B. Walter, A.WojciechowskiPoznan University of Technology, Poznan, Poland

IEEE Joint International Conference onRequirements Engineering

9-13 September 2002, Essen, Germany

IntroductionIntroduction

Tom DeMarcoTom DeMarco

"XP is the most important movement in our field today."

Extreme ProgrammingExtreme Programming (XP) (XP) = =

a lightweight (agile) a lightweight (agile)

software development methodologysoftware development methodology

IntroductionIntroduction

Interesting practices of XPInteresting practices of XP: :

• strong customer orientationstrong customer orientation

• increments & short releasesincrements & short releases

• test-first codingtest-first coding

• planning gameplanning game etc. etc.

IntroductionIntroduction

WeaknessesWeaknesses of XP of XP: :

• lack of documentationlack of documentation

• one (on-site) customerone (on-site) customer

• too short planning perspectivetoo short planning perspective

How to solve those problemsand preserve agility?

ContentsContents

1. Introduction

2. Reconciling XP with documentation3. Multiple customer representatives

4. Modifying the XP lifecycle

5. Early evaluation results

6. Conclusions

Reconciling XP with documentationReconciling XP with documentation

Travel light.Travel light.

Documen-tationDocumen

-tation

Developer

I’ve changed my mind.Let’s go that way.

Customer

Reconciling XP with documentationReconciling XP with documentation

Travel light.Travel light.What you need is justWhat you need is just code and test cases code and test cases. .

I’ve changed my mind.

Customer

code +tests

No problem.

IEEE

Standard 830

UML

Reconciling XP with documentationReconciling XP with documentation

Oral communication is preferred as „Oral communication is preferred as „the written the written and e-mail communications (..) are error-proneand e-mail communications (..) are error-prone”.”.

Why did I decide to ..

Travel light.Travel light.What you need is justWhat you need is just code and test cases code and test cases. .

Error

But people sometimes forget!

Reconciling XP with documentationReconciling XP with documentation

To be agile does not mean that you have to To be agile does not mean that you have to throw away the (requirements) documentation.throw away the (requirements) documentation.

I’ve changed my mind.

Customer

Documen-tation

No problem.

Reconciling XP with documentationReconciling XP with documentation

To be agile does not mean that you have to To be agile does not mean that you have to throw away the (requirements) documentation.throw away the (requirements) documentation.

Documen-tation

No problem.

Developer

I’ve changed my mind.

Customer

Reconciling XP with documentationReconciling XP with documentation

To be agile does not mean that you have to To be agile does not mean that you have to throw away the requirements documentation.throw away the requirements documentation.

XP roles:• Customer• Developer• Coach• Tracker• Tester

In XP tester „is responsible for helping the customer choose and write functional tests”.

-- Kent Beck

Tester-analyst (product manager)is responsible for writing and managing usage scenarios, requirements, and acceptance tests.

Tools: Rational RequisitePro, Rational Robot, xUnit

ContentsContents

1. Introduction

2. Reconciling XP with documentation

3. Multiple customer representatives4. Modifying the XP lifecycle

5. Early evaluation results

6. Conclusions

Weaknesses of XPWeaknesses of XP

If there are many it is assumed they speak one voice.

One on-site customerOne on-site customer

We need a new car. No! We needa new furniture.

Sometimes they don’t.

Multiple customer representativesMultiple customer representatives

Original Planning Game

Effort, risk, velocity

More

colors 9 hours

Writes user stories

More

colors

Chooses scope

More

colors

More

func.

9 h6 h

Multiple customer representativesMultiple customer representatives

Modified Planning Game

Effort, risk, velocity

More

colors 9 hours

They write user stories

More

colors

More

colors

How to choose the scope?

More

colors

More

func.

9 h6 h

Multiple customer representativesMultiple customer representatives

Modified Planning Game

How to choose the scope?

More

colors

More

func.

9 h6 h

20 hours for you ..

Big boss Customers

ContentsContents

1. Introduction

2. Reconciling XP with documentation

3. Multiple customer representatives

4. Modifying the XP lifecycle5. Early evaluation results

6. Conclusions

Modifying the XP LifecycleModifying the XP Lifecycle

One release is sometimes not enough.SShort planning perspective (one release)hort planning perspective (one release)

Utility Technical risk

A spike solution

Design for today, not for tomorrow.Design for today, not for tomorrow.

Modifying the XP LifecycleModifying the XP Lifecycle

One release is sometimes not enough.SShort planning perspective (one release)hort planning perspective (one release)

Utility Technical risk

Design for today, not for tomorrow.Design for today, not for tomorrow.

Modifying the XP LifecycleModifying the XP Lifecycle

0. Initial Project Statement (subject, stakeholders etc.)

1. Usage scenarios (problems + visions)

2. Requirements specification

3. Project presentation & selection of developers

4. Project planning (and risk exploration)

5. Release 1 (2 iterations, each takes 3 weeks)

6. Release 2 (2 iterations)

ContentsContents

1. Introduction

2. Reconciling XP with documentation

3. Multiple customer representatives

4. Modifying the XP lifecycle

5. Early evaluation results6. Conclusions

Software Development Studio – A team structureSoftware Development Studio – A team structure

Project Manager and Analyst

4th yearProject Manager and Analyst

4th year

Quality Manager and Facilitator

5th yearQuality Manager and Facilitator

5th year

Designing, coding, testing,

writing documentation

3rd year

Designing, coding, testing,

writing documentation

3rd year

Experiment at PUTExperiment at PUT

Software Development Studio 2000/01

CMM Level 2 eXtremme Programming

Experiment at PUTExperiment at PUT

Software Development Studio 2001/02

Modified eXtremme Programming

Sommerville-Sawyer ModelSommerville-Sawyer Model

Defined

> 85 Basic & > 40 Interm. + Adv.

Defined

> 85 Basic & > 40 Interm. + Adv.Repeatable

> 55 Basic

Repeatable

> 55 BasicInitial

< 55 Basic

Initial

< 55 Basic

3 – obligatory2 – frequently used1 – sometimes0 – never

Score:RE PracticesBasic• ...• ...

Interm.• ...• ...

Advanced• ...• ...

Basic Int+Adv

TJam 69 31Harpo 71 32Predictor 70 30Kex 68 35EdTool 71 27ASM 64 29

Sommerville-Sawyer ModelSommerville-Sawyer Model

Defined

> 85 Basic & > 40 Interm. + Adv.

Defined

> 85 Basic & > 40 Interm. + Adv.Repeatable

> 55 Basic

Repeatable

> 55 BasicInitial

< 55 Basic

Initial

< 55 Basic

3 – obligatory2 – frequently used1 – sometimes0 – never

Score:

SummarySummary

Tester-analyst is responsible for Tester-analyst is responsible for documenting and managing documenting and managing requirements.requirements.

Modified Planning Game tries to Modified Planning Game tries to solve conflicts between multiple solve conflicts between multiple customers.customers.

Modified life-cycle emphasises Modified life-cycle emphasises requirements engineering and risk requirements engineering and risk management.management.

There is a need for user trainingThere is a need for user training.. Early results are promising.Early results are promising.

QuestionsQuestions??