P a t t e r n s o f A g i l e P r a c t i c e A d o p t i o n A m r E l s s a m a d i s y ID: 737216 www.lulu.com FREE ONLINE EDITION (non-printable free online version) If you like the book, please support the author and InfoQ by purchasing the printed book: http://www.lulu.com/content/737216 (only $24.95) Brought to you Courtesy of This book is distributed for free on InfoQ.com, if you have received this book from any other source then please support the author and the publisher by registering on InfoQ.com. Visit the homepage for this book at: http://www.infoq.com/minibooks/agile-patterns Patterns of Agile Practice Adoption The Technical Cluster Amr Elssamadisy © 2007 C4Media Inc All rights reserved. C4Media, Publisher of InfoQ.com. This book is part of the InfoQ Enterprise Software Development series of books. For information or ordering of this or other InfoQ books, please contact [email protected]. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recoding, scanning or otherwise except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher. Designations used by companies to distinguish their products are often claimed as trademarks. In all instances where C4Media Inc. is aware of a claim, the product names appear in initial Capital or ALL CAPITAL LETTERS. Readers, however, should contact the appropriate companies for more complete information regarding trademarks and registration. Managing Editor: Floyd Marinescu Cover art: Nasser Elssamadisy Composition: Adam Mehling Library of Congress Cataloguing-in-Publication Data: ISBN: 978-1-4303-1488-2 Printed in the United States of America To Samiha and Maha Thank you. Acknowledgements I want to sincerely thank all of the people who have been part of putting together the ideas that went into this book. First on the list is my wife Maha who has been encouraging me, pushing me, pulling me, and generally getting me to write. She also has spent hours of her time editing this book and many of the papers and articles I’ve written this year leading up to this book. Next on my list are Ashley Johnson, Dave West, and Ahmed Elshamy with whom I spent two and a half days with in Arizona in the spring of 2006 during the ChiliPLoP conference discussing patterns, agile practices, and adoption. The four of us shared our experiences over the years and put them in pattern format. After that initial work, Ahmed helped me run a workshop at XP2006 where we presented our ideas and gathered more data for the patterns from over 40 practioners around the world. Ashley spent countless hours discussing the ideas and refining the ideas in this book. Dave and I took the ChiliPLoP work and refined it to present at PLoP 2006 where it was reviewed yet again by another group. Special thanks to Ademar Aguiar for taking the time and effort to shepherd our work for PLoP. Linda Rising and Mary Lynn Manns have also read early versions of this work. Richard Gabriel lead the workshop that reviewed this work, the reviewers were Donald Little, Rebecca Rikner, James F. Kile, Till Schümmer, Lise B. Hvatum, Joseph Bergin, and Guy Steele. Jean Whitmore co-authored a paper with me earlier this year that was the basis for the Functional Tests pattern and Test Driven Requirements cluster. Special thanks to Jason Yip for shepherding this pattern and helping us refine the work for presentation at PLoP. The group that reviewed this pattern included Ralph Johnson, Jason Yip, Hesham Saadawi, Dirk Riehle, Paddy Fagan. The patterns collected in this book are the result of my own experiences and those of many others. This work would not have been possible without the participation of the people who were willing to spend their time, share their knowledge, and struggle to find the commonalities in the ChiliPLoP workshop, XP2006 workshop, and XPDay Montreal 2006 Open Space session (in alphabetical order): Soile Aho, Görge Albrecht, Walter Ambu, Giovanni Asproni, Emine G. Aydal, Meir Ben-Ami, Gilad Bornstein, Filippo Borselli, Ole Dalgaard, Ian Davies, Vasco Duarte, Emmanuel Gaillot, Gabor Gunyho, Janne Hietamäki, Mina Hillebrand, Ashley Johnson, Kan Karkkainen, Tuomas Karkkainen, Maaret Koskenkorva, Krisztina Kovacs, Juha Laitinen, Andreas Larsson, Mikko Levonmaa, Youri Metchev, Aivar Naaber, Paul Nagy, Keijo Niinimaa, Loua Nordgvist, Virva Nurmua, Marko Oikarinen, Jukka Ollakka, Paolo Perrotta, Dimitri Petchatnikov, Ron Pijpers, Aussi Piirainen, Ilja Preus, Timo Pulkkinen, Niko Ryytty, Abdel Aziz Saleh, Aki Salmi, Meelis Salvvee, Timo Taskinen, Olavi Tiimus, Ingmar van Dijk, Jussi Vesala, Daniel Wellner. Filippo Borselli, John Mufarrige, Ron Jeffries, Floyd Marinescue, Deborah Hartmann, and Kurt Christenson took the time to read drafts of this work and give their feedback to make this a much better work that it was originally. Finally, thanks to Floyd Marinescue and Deborah Hartmann from InfoQ for giving me the opportunity to write this book and make it available to the public. Amr Elssamadisy Amherst Massachusetts December 9th 2006 Table of Contents Foreword by Ron Jeffries ii Foreword by Craig Larman vi Is This Book for You? xiii Introduction xv The Plan xv Scope xvi How to Read this Book xvii Part 1: Business Value, Smells, and an Adoption Strategy 19 1. Business Value 20 Reduce time to market 21 Increase value to market 22 Increase quality to market 22 Increase flexibility 23 Increase visibility 23 Reduce cost 24 Increase product lifetime 24 Theory to Practice: Determining Your Organization’s Business Values 25 2. Smells 27 Business Smells 28 Process Smells 30 Theory to Practice: What Smells Can You Find? 34 3. Adopting Agile Practices 37 Pattern to Business Value Mappings 38 Pattern to Smell Mappings 40 Be Business-Value Focused 41 Be Goal-Oriented 42 Adopt Iteratively 42 Be Agile About Your Adoption 43 Test-Driven Adoption Strategies 43 Theory to Practice: Building Your Own Agile Practice Adoption Strategy 45 Part 2: The Patterns 47 4. Introduction 49 What is a Pattern? 49 Using Patterns Effectively 51 5. Automated Developer Tests (Abstract Pattern) 55 6. Test-Last Development (Implements Automatic Developer Tests) 67 7. Test-First Development (Implements Automatic Developer Tests) 73 8. Refactoring 81 9. Continuous Integration 87 10. Simple Design 97 11. (Automated) Functional Tests 105 12. Collective Code Ownership 123 Part 3: The Clusters 129 13. Clusters of Practices 131 14. Evolutionary Design 133 15. Test Driven Development 141 16. Test Driven Requirements 149 Conclusion 157 Appendices 159 17. Pattern to Business Value Mappings 161 18. Pattern to Smell Mappings 163 19. Adoption Strategy Case Study 167 Introduction 167 Crafting an Agile Practice Adoption Strategy 168 20. Patterns of Agile Practices Referenced but Not Defined 175 21. Getting the Most from Agile Practice Patterns 177 22. Reading a Pattern Effectively 179 Bibliography 183 About the Author 185