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An Introduction to AgileEngineering Practices

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Kane Mar

Danube Technologies, Inc

The New New ProductDevelopment Game

- Takeuchi and Nonaka

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photo: http://www.flickr.com/photos/nicmcphee/

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From: Kent Beck

To: Jeff Sutherland

Reply: [email protected]

Date: Mon, 15 May 1995 18:01:15 -0400 (EDT)Subj: HBR paper

_________________________Is there a good place to get reprints of the SCRUM paper fromHBR? I've written patterns for something very similar and I want tomake sure I steal as many ideas as possible.

Kent

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Continuous Integration


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What is ContinuousIntegration?

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Continuous Integration is a softwaredevelopment practice where members of a

team integrate their work frequently,usually each person integrates at least daily- leading to multiple integrations per day.

Each integration is verified by anautomated build (including test) to detectintegration errors as quickly as possible.

-Martin Fowler

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Commit

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1. Compile & Build2. Unit Tests3. Integration Tests4. Report Errors

Commit


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Commit

Checkout

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Commit

Checkout


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Commit

Checkout

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Why is Continuous Integrationimportant?

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1. Reducing Risk.

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When we are integrating theproduct all the time the risk of a

failed integration is spreadthroughout the duration of the

project ...

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rather than being left until theend.

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2. Behavior.

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If doing a complete build andtest of any product is difficult ...

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doing it continuously is verydifficult.

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Teams need to develop differentways of working.

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Never letting the build break.

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Commit

CheckoutA broken build orintegration test

here ...


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Commit

CheckoutA broken build orintegration testhere ...

will get propagatedhere, here and here.

The Friday Afternoon Pattern ofbroken builds.

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Delivering smaller incrementsof well tested functionality.

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Investing in automated testingframeworks.

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Test, Test and Test again.

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I believe that allteams shouldpractice CI.

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The tools are free, like free beer.

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The only price to pay forintroducing CI is ...

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education.

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http://www.martinfowler.com/articles/continuousIntegration.html

http://cruisecontrol.sourceforge.net/

http://www.jetbrains.com/teamcity/

http://luntbuild.javaforge.com/

https://hudson.dev.java.net/

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References


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Test Driven Development

What is Test DrivenDevelopment?

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1. Add a test

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2. Run all test and see the newones fail

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3. Write some code

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4. Run the automated tests andsee them succeed

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5. Refactor

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Red/Green/Refactor

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Why is TDD important?

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TDD is a method of designingsoftware, not merely an

approach to testing.

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We found that test-firststudents on average wrote moretests and, in turn, students whowrote more tests tended to be

more productive.

- Erdogmus, Hakan; Morisio,

Torchiano45

Over a period of time, TDD willlead to suite of automated

integration tests.

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Erdogmus, Hakan; Morisio, Torchiano. On the Effectiveness of Test-firstApproach to Programming, Proceedings of the IEEE Transactions on Software

Engineering, 31(1). January 2005. (NRC 47445). We found that test-first students

on average wrote more tests and, in turn, students who wrote more tests tended tobe more productive.

Newkirk, JW and Vorontsov, AA. Test-Driven Development in Microsoft .NET,Microsoft Press, 2004.

Feathers, M. Working Effectively with Legacy Code, Prentice Hall, 2004

Beck, K. Test-Driven Development by Example, Addison Wesley, 2003

Muller, Matthias M.; Padberg, Frank. About the Return on Investment of Test-Driven Development (PDF) Universitat Karlsruhe, Germany

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References

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Refactoring


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What isRefactoring?

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Refactoring is a disciplined technique forrestructuring an existing body of code,altering its internal structure without

changing its external behavior.- Martin Fowler

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Each transformation (called a 'refactoring')does little, but a sequence of

transformations can produce a significantrestructuring.

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double disabilityAmount() {if (_seniority < 2) return 0;if (_monthsDisabled > 12) return 0;if (_isPartTime) return 0;// compute the disability amount

double disabilityAmount() {if (isNotEligableForDisability()) return 0;// compute the disability amount

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Refactoring is a disciplined technique forrestructuring an existing body of code,altering its internal structure without

changing its external behavior.- Martin Fowler

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How do we establish that thebehavior is unchanged?

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Continuous Integration

and

Test Driven Development

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The termRefactoring is poorlyused.

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If somebody talks about asystem being broken for a

couple of days while they arerefactoring ...

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you can be pretty sure they arenot refactoring ...

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Refactoring is a very specifictechnique, founded on using

small behavior-preservingtransformations

- Martin Fowler

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Fowler, Martin (1999). Refactoring. Addison-Wesley. ISBN 0-201-48567-2.

http://martinfowler.com/bliki/RefactoringMalapropism.html

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References


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Pair Programming

What isPair Programming?

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Two team members working onthe same code base and working

side-by-side

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photo: http://www.flickr.com/photos/improveit/

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I told you Slashdot was more popular than Digg

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Modern software development is full of drama ...

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The thrill of victory ...

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And the agony of defeat.

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Why isPair Programmingimportant?

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Pair Programming significantlyreduces the number of defects,and greatly increase the quality

of the code.

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It is, however, very difficult tointroduce.

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There are many issues mostlyrelated to loss of personal space

and lack of privacy.

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Why do we care?

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80% of the cost of software isincurred after it has gone live.

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What would it mean to you ifyour cost of change was linear

rather than exponential?

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Thank You!

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