1.
An Introduction to Agile
Engineering Practices
Kane Mar
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2.
“The New New Product
Development 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 <jsutherland>
Reply: 70761.1216@compuserve.com
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 from
HBR? I've written patterns for something very similar and I want to
make sure I steal as many ideas as possible.
Kent
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6.
Continuous Integration
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What is Continuous
Integration?
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“Continuous Integration is a software
development 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 an
automated build (including test) to detect
integration errors as quickly as possible.”
-Martin Fowler
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9.
Commit
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1. Compile & Build
Commit 2. Unit Tests
3. Integration Tests
4. Report Errors
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11.
1. Compile & Build
Commit 2. Unit Tests
3. Integration Tests
4. Report Errors
Checkout
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12.
1. Compile & Build
Commit 2. Unit Tests
3. Integration Tests
4. Report Errors
Checkout
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13.
1. Compile & Build
Commit 2. Unit Tests
3. Integration Tests
4. Report Errors
Checkout
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14.
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Why is Continuous Integration
important?
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1. Reducing Risk.
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When we are integrating the
product all the time the risk of a
failed integration is spread
throughout the duration of the
project ...
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rather than being left until the
end.
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2. Behavior.
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If doing a complete build and
test of any product is difficult ...
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doing it “continuously” is very
difficult.
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Teams need to develop different
ways of working.
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Never letting the build break.
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1. Compile & Build
Commit 2. Unit Tests
3. Integration Tests
4. Report Errors
A broken build or
Checkout integration test
here ...
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1. Compile & Build
Commit 2. Unit Tests
3. Integration Tests
4. Report Errors
A broken build or
Checkout integration test
here ...
will get propagated
here, here and here.
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26.
The Friday Afternoon Pattern of
broken builds.
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Delivering smaller increments
of well tested functionality.
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Investing in automated testing
frameworks.
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Test, Test and Test again.
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I believe that all teams should
practice CI.
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The tools are free, like free beer.
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The only price to pay for
introducing CI is ...
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education.
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References
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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35.
Test Driven Development
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What is Test Driven
Development?
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1. Add a test
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2. Run all test and see the new
ones fail
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3. Write some code
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4. Run the automated tests and
see 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 designing
software, not merely an
approach to testing.
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“We found that test-first
students on average wrote more
tests and, in turn, students who
wrote more tests tended to be
more productive.”
- Erdogmus, Hakan; Morisio,
Torchiano
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Over a period of time, TDD will
lead to suite of automated
integration tests.
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References
Erdogmus, Hakan; Morisio, Torchiano. “On the Effectiveness of Test-first
✦
Approach 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 to
be 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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Refactoring
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What is Refactoring?
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“Refactoring is a disciplined technique for
restructuring 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 significant
restructuring.”
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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 for
restructuring 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 the
behavior is unchanged?
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Continuous Integration
and
Test Driven Development
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The term Refactoring is poorly
used.
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“If somebody talks about a
system being broken for a
couple of days while they are
refactoring ...”
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“you can be pretty sure they are
not refactoring ... “
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“Refactoring is a very specific
technique, founded on using
small behavior-preserving
transformations”
- Martin Fowler
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References
Fowler, Martin (1999). “Refactoring.” Addison-Wesley. ISBN 0-201-48567-2.
✦
http://martinfowler.com/bliki/RefactoringMalapropism.html
✦
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61.
Pair Programming
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What is Pair Programming?
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Two team members working on
the 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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photo: http://www.flickr.com/photos/improveit/
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photo: http://www.flickr.com/photos/improveit/
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The thrill of victory ...
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And the agony of defeat.
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Why is Pair Programming
important?
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Pair Programming significantly
reduces the number of defects,
and greatly increase the quality
of the code.
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It is, however, very difficult to
introduce.
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There are many issues mostly
related 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 is
incurred after it has gone live.
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What would it mean to you if
your cost of change was linear
rather than exponential?
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Thank You!
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