http://www.infoq.com/interviews/coplien-martin-tdd

Thanks Cope, thanks Bob.

James O. Coplien has recently argued that today’s industry is based on buzzwords and checklists. The use of some techniques and methodologies, TDD for instance, has become “a religious issue”. This prevents from inspecting possible tradeoffs and focusing on finding solutions that would be the most appropriate and the most cost-effective .

“For some reason, we have invented and are following religions […].” This is how James O. Coplien describes today’s industry which, he believes, is based on buzzwords and checklists rather than on thinking, inspection and efforts to find solutions that would be the most appropriate and the most cost-effective for a given project:

How much thought did you put into the tradeoffs of the last technique you brought into your organization: Ajax, TDD, On-Site Customer, or other buzzwords? Did you research its track record? Or did you go to the buzzword yellow pages?

James uses the example of the debate around TDD which has occurred in the blog space in the wake of Jaoo 2007 conference. When the discussion focuses on what approach to testing is the best (i.e. TDD or acceptance testing), it essentially addresses the wrong question. It obfuscates the real objective which is “to deliver what the customer wanted while optimizing quality” and to create value for the client. Testing is what we have on today’s checklist for quality but it is far from covering all the issues that actually affect quality:

Quality suffers if you misunderstand what the customer wanted, or if the code has internal interactions that are difficult to foresee, or if local code violates array boundaries or uses untethered pointers. It also suffers if the interface makes it possible for the user to commit errors, or if it takes too many keystrokes to enter a small amount of common information.

Focusing on quality requires considering every weapon in the arsenal:

That means using Use Cases (which are an Agile way of engaging customers […]) instead of XP-style user stories (so you understand feature interactions up-front), doing pair programming or desk-check code inspections, doing design by contract, driving the process with usability experts and doing good usability testing, and a host of other things.

Coplien emphasizes that it is impossible to do everything and that it is “a matter of cost effectiveness”. But being focused on techniques and driven by buzzwords we get stuck in practices that might not be optimal. The use of some techniques and methodologies, e.g. TDD, has become “a religious issue”, according to James:

We are told that you have to do TDD to be a professional […] and yet are given no reason to believe this, no substantiation, and no evidence. Just believe.

Coplien argues, for instance, that “integration and system testing have long been demonstrated to be the least efficient way of finding bugs”, that TDD “deteriorates the architecture”, and that “acceptance testing is orders of magnitude less efficient than good old-fashioned code inspections, extremely expensive, and comes too late to keep the design clean.” But he stresses how difficult it is to engage a challenging discussion on such “religious” topics because any criticism is met with a lot of emotion.

People have tied their Agile success to their introduction of TDD practices into their work. It’s the one thing they can do as individuals rather than as an enterprise.

Coplien advocates for focusing on quality rather than testing and, more generally speaking, on thinking rather than checklists. He highlights however that “sorting these things out requires a system view”, which often times lacks in today’s industry. He believes that “New Age Agile movements consistently move away from” systems engineering. According to Coplien, “one root of the problem lies in modern education, which has increased its focus on technique and reduced its focus on thinking.” Today’s students “fewer and fewer understand software history” and “have stronger memories […]on exactly when to use --v and when to use v-- than they recall anything about logical design.”

Close links which exist between academia and industry are also a part of the problem. Universities tend to adapt curricula to industry’s needs in order to facilitate students’ placement. Hence, it becomes difficult for academics to challenge predominate views, probably “as difficult as it was for Newton” to prevail “with new insights on the working of the universe”:

In fighting the broad misunderstandings that industry has chosen to adopt from selected interpretations of Agile, SOA, and programming language buzzwords, we face no less a religion, and no less threat to our cozy industry-financed academic positions, than he did.

I just got back from JAOO2007. One session of the conference was James Coplien’s “Scrum Architecture”. After this session, a discussion took place about Coplien’s statement that “TDD harms your architecture”! This discussion continued afterwards as an Open Spaces debate. I had the chance then, with the help of Floyd Marinescu, to organize a filmed debate at InfoQ’s studio between Bob Martin and James Coplien on the same topic. I really enjoyed this debate which really showed a high quality spirit of discussion from both sides. Both had their arguments. I will not tell my opinion but rather let you judge yourself once the video is out on www.InfoQ.com .

Recently, I posted about the fact that I always write tests before code, but I don’t do Test Driven Development where I discussed the way I view testing. Yet I don’t guess I’ve been clear enough, so I decided to write few lines trying to better reflect the way I view a testing approach.

When I have a domain problem at hand, first what I think about is partitioning and abstraction, which means dividing the domain into sub-domains. This partitioning procedure is not driven by any tests, but rather by domain knowledge acquired from domain experts. This is extremely important; the architecture/design should reflect the domain/sub-domain problem it is trying to solve. This helps the software be flexible adopting business changes, as it was designed from a business perspective. A book that explains very well this approach is Eric Evans’s Domain Driven Design.

This Up-Front analysis is not defining the full up-front architecture, far from it, rather defining good bases for an architecture that maps to business. It shouldn’t take much time, just enough to help going forward with an iterative approach. This should define, either in code or in a tinny UML sketch, an object structure that forms the basic sub-domain’s components.

After defining the main structure of the sub-domain’s solution, I follow an iterative process as follows:

1: Driven by the business knowledge crunching, I define a component’s contract with its invariants and conditions

2: I write a test that forms the specification of this contract and its invariants

3: I start the implementation to satisfy the specifications I defined in the test

A very important note here is that the contract specifications should be readable, very clear and explicit. This explicitness helps to have a better vision of the whole system while reading the contracts-invariants of its defined components. This also helps spot bugs without the painful debugging: this approach of Design by Contract reflects developers understanding of the business domain in a more explicit way, so it makes it easier to spot misjudgments developers might have done in their implementation. This intention revealing method of development highlights important business rules, rather than letting them hidden behind an abstraction. Abstractions should not hide any important business concern as an implementation details. Explicit contracts and invariants allow business experts to have a look on what is going on inside the software. For an example of bugs that result from developer’s misjudgment see Reganwald’s recent post .

Of course unit tests are not the best tools for this approach. They work fine if we emphasize on methods and class naming for readability and visibility of invariants and rules. Still I prefer tools like BDD or Eiffel/Spec# Design by Contract. Hope we will have some more support for such tools in the industry soon.

A metaphor James Coplien used to illustrate the problem in Test Driven Development approach, which made sense to me, is a test driven course in a school. It’s about a teacher that finds that most of his students fail in the final test. So to make things work better, he decided to ask the students to write themselves their tests by the beginning of the semester, and then to let them pass these tests by the end of that semester! Hence, they might get better grades, but that doesn’t mean they got better knowledge at all.

 

It is always a hard choice for such an interesting conference, I scheduled my first day, still couldn’t decide about some session. I’ll be trying to make some sort of live coverage with my laptop :) as I did for QCon2007

Tuesday  Architecture Quality (day 1)  Enterprise Application Frameworks (day 1)  LINQ  Modeling  Scrum At JAOO2007  Solution Track : Tuesday  Web 2.0 Host Frank Buschmann Eberhard Wolff Mads Torgersen Rebecca Wirfs-Brock Jeff Sutherland Beat Schwegler 09:15 - 10:00 Democratizing the Cloud Track host: Erik Meijer 10:00 - 10:30 Break 10:30 - 10:45 Introduction: Architecture Quality (day1) Track host: Frank Buschmann Location: Conference Hall Introduction: Enterprise Application Frameworks (day 1) Track host: Eberhard Wolff Location: SAS Nortvegia Introduction: LINQ Speakers: TBA Location: SAS Dania Introduction: Design and Modeling Track host: Rebecca Wirfs-Brock Location: Conference Hall 3 Introduction: Scrum at JAOO Track host: Jeff Sutherland Location: Conference Hall 2 Spring SpaceCraft Shay Banon Introduction: Web 2.0 Track host: Beat Schwegler Location: SAS Suecia 10:45 - 11:00 Break 11:00 - 12:00 Architecting for Software Product Lines Jan Bosch Location: Conference Hall Painless Persistence with Castle ActiveRecord Hamilton Verissimo & Oren Eini Location: SAS Nortvegia The .NET Language Integrated Query (LINQ) Framework Luca Bolognese Location: SAS Dania Models that work: When Model Engineering Meets Open Source Jean Bezivin Location: Conference Hall 3 Planning in Large Companies Hubert Smits Location: Conference Hall 2 JBoss – The professional Open Source SOA Platform Michael Martinsen Building Rich Internet Applications for the Browser and the Desktop with Flex and AIR Christophe Coenraets Location: SAS Suecia 12:00 - 13:00 Lunch 13:00 - 14:00 Managing Variability in Product-Lines Track host: Markus Völter Location: Conference Hall Leveling Persistence and State Management Technologies with Spring Track host: Eberhard Wolff Location: SAS Nortvegia C# 3.0 under the hood Track host: Mads Torgersen Location: SAS Dania Strategic Design Eric Evans Location: Conference Hall 3 Implementing Type C Scrum in different corporate models Evan Campbell Location: Conference Hall 2 Inside JavaBlackBelt John Rizzo Building Large Applications with GWT 1.4 Rajeev Dayal Location: SAS Suecia 14:00 - 14:20 Break 14:20 - 15:20 Complexity Management Klaus Marquardt Location: Conference Hall Active Record – Easy Living on the Golden Path Chad Fowler Location: SAS Nortvegia LINQ to XML Track host: Erik Meijer Location: SAS Dania Things your mother didn’t tell you about architecture and GUIs Trygve Reenskaug Location: Conference Hall 3 Scrum Architecture Jim O. Coplien Location: Conference Hall 2 The Heretic’s View of Java Persistence Mike Fuller From HTML to XUL, Web to Desktop Shane Caraveo Location: SAS Suecia 15:20 - 15:40 Break 15:40 - 16:40 Variability (and) Modeling Krzysztof Czarnecki Location: Conference Hall Grails: Next Generation Spring plus Hibernate Development Graeme Rocher Location: SAS Nortvegia Using LINQ to SQL to Access Relational Data Luca Bolognese Location: SAS Dania The Adaptive Object-Model Architecture: Giving users control over their business model Joseph Yoder Location: Conference Hall 3 Scrum@British Telecom Geoff Watts & Paul Goddard Location: Conference Hall 2 CruiseControl Track host: Erik Dörnenburg & Chris Read JavaFX Speakers: TBA Location: SAS Suecia 16:40 - 16:55 Break 16:55 - 17:55 The Symphonia Product-Line Wolfgang Strunk Location: Conference Hall JCR in the Real World Alexandru Popescu Location: SAS Nortvegia LINQ for Domain Driven Design (DDD) Kim Harding Christensen & Jimmy Nilsson Location: SAS Dania Muddle-Driven Marketecture or Model-Driven Tarchitecture? Cris Kobryn Location: Conference Hall 3 Heartbeat Retrospectives Boris Gloger Location: Conference Hall 2 Using the public Danish SOA Infrastructure Speakers: TBA The Overlooked Power of JavaScript Track host: Glenn Vanderburg Location: SAS Suecia 17:55 - 18:05 Break 18:05 - 18:50 Sun Keynote Matt Thompson 18:50 - 19:00 Break 19:00 - 21:00 JAOO IT-Run 21:00 - 23:00 Jam Session

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Wednesday	 Architecture Quality (day 2)	 Enterprise Application Frameworks (day 2)	 Professional Developer	 Public Sector Open Source	 Scrum at JAOO: Case Studies	 Scrum: Open Space Discussions	 Solution Track: Wednesday
Host	Frank Buschmann	Erik Doernenburg	Bob Martin	Mogens Kühn Pedersen	TBA	Facilitator: Diana Larsen & Jens Østergaard
09:00 - 09:15	Introduction: Architecture Quality (day2) Track host: Frank Buschmann Location: Conference Hall	Introduction: Enterprise Application Frameworks (day 2) Track host: Erik Dörnenburg Location: SAS Nortvegia	Introduction: Professional Developer Track host: Robert C. Martin Location: Conference Hall 3	Introduction: Public Sector Open Source Mogens Kühn Pedersen Location: SAS Dania	Introduction: Case Studies Speakers: TBA Location: Conference Hall 2	Introduction: Open Space Speakers: TBA
09:15 - 09:30	Break
09:30 - 10:30	Operational Scalability in the Next-Gen-Web World Wayne Fenton Location: Conference Hall	MonoRail: Building Maintainable & Testable Web Applications Hamilton Verissimo & Oren Eini Location: SAS Nortvegia	With Economy and Elegance Kevlin Henney Location: Conference Hall 3	Developing and Sustaining Local Authority Applications through Aingaran Pillai Location: SAS Dania	Scrum@Planon Erik Jaspers & Maarten Smeets Location: Conference Hall 2	Open Space (1) Speakers: TBA	ServiceMix 4.0, the next generation ESB Guillaume Nodet
10:30 - 11:00	Break
11:00 - 12:00	Fault Tolerance Robert S. Hanmer Location: Conference Hall	Choosing the right technology for the web-tier Alef Arendsen Location: SAS Nortvegia	The Journeyman’s Tale Laurent Bossavit Location: Conference Hall 3	OSS Electronic Health Care Records; Vista in Denmark Martin Sølvkjær Location: SAS Dania	Scrum@Telenor Peter Johansson & Arne Ahlander Location: Conference Hall 2	Open Space (2) Speakers: TBA	Infragistics Speakers: TBA
12:00 - 13:00	Lunch
13:00 - 14:00	Performance Art Kevlin Henney Location: Conference Hall	Ruby on Rails – ActionPack Justin Gehtland Location: SAS Nortvegia	The Ethics of Error-Prevention Michael Feathers Location: Conference Hall 3	An Open Source Strategy for a nation Bruno F. Souza Location: SAS Dania	Scrum@Yahoo Gabrielle Benefield Location: Conference Hall 2	Open Space (3) Speakers: TBA	Architecture for a European SOI for e-procurement Speakers: TBA
14:00 - 14:30	Break
14:30 - 15:30	Lessons Learned From Architecture Reviews Track host: Rebecca Wirfs-Brock Location: Conference Hall	Case Study: The New Guardian.co.uk Track host: Erik Dörnenburg & Matthew Wall Location: SAS Nortvegia	Applying Craftsmanship Pete McBreen Location: Conference Hall 3	History of B103 and ODF,OOXML Panel Discussion Rachid El Mousti & René Løhde & Florian Reuter Location: SAS Dania	Scrum@Nokia Bas Vodde Location: Conference Hall 2	Open Space (4) Speakers: TBA	Open UDDI Speakers: TBA
15:30 - 16:00	Break
16:00 - 17:00	Panel: Does Architecture Quality Matter? Kevlin Henney & Klaus Marquardt & Track host: Frank Buschmann & Jan Bosch & Track host: Rebecca Wirfs-Brock Location: Conference Hall	Panel: Enterprise Application Frameworks Justin Gehtland & Track host: Erik Dörnenburg & Graeme Rocher & Alef Arendsen & Oren Eini & Track host: Eberhard Wolff Location: SAS Nortvegia	Finding your Inner Doll – Layers of a Professional Ilja Preuss Location: Conference Hall 3	Panel: Shared Business Application Systems Martin Niels Pedersen & Mogens Kühn Pedersen & Martin Sølvkjær Location: SAS Dania	Scrum@Bang&Olufsen Jørn A. Hansen & Chris Thomasen Location: Conference Hall 2	Open Space (5) Speakers: TBA
17:00 - 17:15	Break
17:15 - 18:15	Final Panel Martin Fowler Location: Conference Hall 3