From the Book:
“Clean code that works” is Ron Jeffries’ pithy phrase. The goal is clean code that works, and for a whole bunch of reasons:
Clean code that works is a predictable way to develop. You know when you are finished, without having to worry about a long bug trail.Clean code that works gives you a chance to learn all the lessons that the code has to teach you. If you only ever slap together the first thing you think of, you never have time to think of a second, better, thing. Clean code that works improves the lives of users of our software.Clean code that works lets your teammates count on you, and you on them.Writing clean code that works feels good.But how do you get to clean code that works? Many forces drive you away from clean code, and even code that works. Without taking too much counsel of our fears, here’s what we do—drive development with automated tests, a style of development called “Test-Driven Development” (TDD for short). 
In Test-Driven Development, you:
Write new code only if you first have a failing automated test.Eliminate duplication.

Two simple rules, but they generate complex individual and group behavior. Some of the technical implications are:You must design organically, with running code providing feedback between decisionsYou must write your own tests, since you can’t wait twenty times a day for someone else to write a testYour development environment must provide rapid response to small changesYour designs must consist of many highly cohesive, loosely coupled components, just to make testing easy

The two rules imply an order to the tasks ofprogramming:
1. Red—write a little test that doesn’t work, perhaps doesn’t even compile at first
2. Green—make the test work quickly, committing whatever sins necessary in the process
3. Refactor—eliminate all the duplication created in just getting the test to work


Red/green/refactor. The TDD’s mantra.

Assuming for the moment that such a style is possible, it might be possible to dramatically reduce the defect density of code and make the subject of work crystal clear to all involved. If so, writing only code demanded by failing tests also has social implications:
If the defect density can be reduced enough, QA can shift from reactive to pro-active workIf the number of nasty surprises can be reduced enough, project managers can estimate accurately enough to involve real customers in daily developmentIf the topics of technical conversations can be made clear enough, programmers can work in minute-by-minute collaboration instead of daily or weekly collaborationAgain, if the defect density can be reduced enough, we can have shippable software with new functionality every day, leading to new business relationships with customers


So, the concept is simple, but what’s my motivation? Why would a programmer take on the additional work of writing automated tests? Why would a programmer work in tiny little steps when their mind is capable of great soaring swoops of design? Courage.
Courage
Test-driven development is a way of managing fear during programming. I don’t mean fear in a bad way, pow widdle prwogwammew needs a pacifiew, but fear in the legitimate, this-is-a-hard-problem-and-I-can’t-see-the-end-from-the-beginning sense. If pain is nature’s way of saying “Stop!”, fear is nature’s way of saying “Be careful.” Being careful is good, but fear has a host of other effects:
Makes you tentativeMakes you want to communicate lessMakes you shy from feedbackMakes you grumpy

None of these effects are helpful when programming, especially when programming something hard. So, how can you face a difficult situation and:
Instead of being tentative, begin learning concretely as quickly as possible.Instead of clamming up, communicate more clearly.Instead of avoiding feedback, search out helpful, concrete feedback.(You’ll have to work on grumpiness on your own.) 

Imagine programming as turning a crank to pull a bucket of water from a well. When the bucket is small, a free-spinning crank is fine. When the bucket is big and full of water, you’re going to get tired before the bucket is all the way up. You need a ratchet mechanism to enable you to rest between bouts of cranking. The heavier the bucket, the closer the teeth need to be on the ratchet.

The tests in test-driven development are the teeth of the ratchet. Once you get one test working, you know it is working, now and forever. You are one step closer to having everything working than you were when the test was broken. Now get the next one working, and the next, and the next. By analogy, the tougher the programming problem, the less ground should be covered by each test.

Readers of Extreme Programming Explained will notice a difference in tone between XP and TDD. TDD isn’t an absolute like Extreme Programming. XP says, “Here are things you must be able to do to be prepared to evolve further.” TDD is a little fuzzier. TDD is an awareness of the gap between decision and feedback during programming, and techniques to control that gap. “What if I do a paper design for a week, then test-drive the code? Is that TDD?” Sure, it’s TDD. You were aware of the gap between decision and feedback and you controlled the gap deliberately.

That said, most people who learn TDD find their programming practice changed for good. “Test Infected” is the phrase Erich Gamma coined to describe this shift. You might find yourself writing more tests earlier, and working in smaller steps than you ever dreamed would be sensible. On the other hand, some programmers learn TDD and go back to their earlier practices, reserving TDD for special occasions when ordinary programming isn’t making progress.

There are certainly programming tasks that can’t be driven solely by tests (or at least, not yet). Security software and concurrency, for example, are two topics where TDD is not sufficient to mechanically demonstrate that the goals of the software have been met. Security relies on essentially defect-free code, true, but also on human judgement about the methods used to secure the software. Subtle concurrency problems can’t be reliably duplicated by running the code.

Once you are finished reading this book, you should be ready to:
Start simplyWrite automated testsRefactor to add design decisions one at a time

This book is organized into three sections.
An example of writing typical model code using TDD. The example is one I got from Ward Cunningham years ago, and have used many times since, multi-currency arithmetic. In it you will learn to write tests before code and grow a design organically.An example of testing more complicated logic, including reflection and exceptions, by developing a framework for automated testing. This example also serves to introduce you to the xUnit architecture that is at the heart of many programmer-oriented testing tools. In the second example you will learn to work in even smaller steps than in the first example, including the kind of self-referential hooha beloved of computer scientists.Patterns for TDD. Included are patterns for the deciding what tests to write, how to write tests using xUnit, and a greatest hits selection of the design patterns and refactorings used in the examples.

I wrote the examples imagining a pair programming session. If you like looking at the map before wandering around, you may want to go straight to the patterns in Section 3 and use the examples as illustrations. If you prefer just wandering around and then looking at the map to see where you’ve been, try reading the examples through and refering to the patterns when you want more detail about a technique, then using the patterns as a reference.

Several reviewers have commented they got the most out of the examples when they started up a programming environment and entered the code and ran the tests as they read.

A note about the examples. Both examples, multi-currency calculation and a testing framework, appear simple. There are (and I have seen) complicated, ugly, messy ways of solving the same problems. I could have chosen one of those complicated, ugly, messy solutions to give the book an air of “reality.” However, my goal, and I hope your goal, is to write clean code that works. Before teeing off on the examples as being too simple, spend 15 seconds imagining a programming world in which all code was this clear and direct, where there were no complicated solutions, only apparently complicated problems begging for careful thought. TDD is a practice that can help you lead yourself to exactly that careful thought.

Test Driven Development: By Example

The Ponder language provides a common means of specifying security policies that map onto various access control implementation mechanisms for firewalls, operating systems, databases and Java. It supports obligation policies that are event triggered condition-action rules for policy based management of networks and distributed systems. Ponder can also be used for security management activities such as registration of users or logging and auditing events for dealing with access to critical resources or security violations. Key concepts of the language include roles to group policies relating to a position in an organisation, relationships to define interactions between roles and management structures to define a configuration of roles and relationships pertaining to an organisational unit such as a department. These reusable composite policy specifications cater for the complexity of large enterprise information systems. Ponder is declarative, strongly-typed and object-oriented which makes the language flexible, extensible and adaptable to a wide range of management requirements.

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The Ponder Policy Specification Language

https://onlinelibrary.wiley.com/doi/pdf/10.1002/stvr.247

Problem frames: analyzing and structuring software development problems. By Michael Jackson. Published by Addison‐Wesley, Boston, Massachusetts, U.S.A., ACM Press Series, 2001. ISBN: 0‐201‐59627‐X, 390 pages. Price: U.K. ?32.95, U.S.A. $49.99, soft cover.

This instalment of the Software Technology department discusses how the digital transformation is affecting software technology and the software industry.

Digital Transformation

Enterprise Application Integration

Foreword Part I: Introduction and Fundamentals 1. The Management of Networked Systems -Task Definition 2. Fundamental Structures of Networked Systems 3. Requirements of the Management of Networked Systems Part II - Management Architectures 4. Management Architectures and Their Submodels 5. OSI Management 6. Internet Management 7. CORBA as a Management Architecture 8. DMTF Desktop Management Interface 9. Web-based Management Architectures 10. Gateways Between Management Architectures PART III: Management Tools 11. Classification of Management Tools 12. Standalone Test and Monitoring Tools 13. Management Platforms 14. Enterprise Tools 15. Development Tools 16. Selected Solutions and Tools for Network and Systems Management PART IV: Operational Use 17. Introduction to the Operation of a Networked System 18. Use of Management Tools in Operation 19. Quality Monitoring and Assurance of Operations 20. Two Examples of Provider-Oriented Management Products PART V: Outlook 21. Future Requirements and Solutions for IT Management 22. Management Architectures and Information Models 23. Management: Driving Force or Impediment? Bibliography Abbreviations Index

Integrated Management of Networked Systems: Concepts, Architectures and their Operational Application

A software application has strong relationships with the business processes it supports. In the analysis phase those parts of the processes in which the software system is applied by its future users are analyzed. Taking an object-oriented approach, the Unified Modeling Language (UML) is often used to model the relevant aspects of the business processes. In the design phase these models must be manually mapped to the business layer of the software application. The Service-Oriented Architecture (SOA) offers a promising new approach: The business process is described in a programming language [1], i.e. a process language which can be automatically mapped to an execution language and executed by a process engine. This article shows how Programming in the Large can be practically applied in a software engineering process. The Business Process Model Notation (BPMN) is used as a process programming language. A BPMN description can be mapped to the widely accepted Business Process Execution Language (BPEL).

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Development of SOA-Based Software Systems - an Evolutionary Programming Approach

With the mutual consent to use WSDL (Web Service Description Language) to describe web service interfaces and SOAP as the basic communication protocol, the cornerstone for web service-oriented architecture (WSOA) has been established. Considering the momentum observable by the growing number of specifications in the web service domain for the indispensable cross-cutting concern of identity management (IdM) it is still an open issue how a WSOA-aware IdM architecture is built and how it is linked with WSOA's main elements, the web services providing functional core concerns. In this paper we present an access control model for WSOA and a blueprint of a WSOA- aware authorization verification service which is part of the IdM architecture. We show the integration of this service with WSOA consisting of both basic and composite web services. Our solution has been tested and evaluated in an implementation case study.

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An Access Control Metamodel for Web Service-Oriented Architecture

Preface Part I: Foundations *1 Foundations of communication systems and distributed systems Architectures * Protocols * Resources *2 Foundations of network management and system management Network management from the provider's point of view * Management dimensions * Differentiation between network and system management Part II: Management Architectures *3 Need for and requirements of integrated management *4 Submodels of a network management architecture Information model * Organizational model * Communication model * Functional model *5 OSI network management Overview * OSI information model * OSI organizational model * OSI communication model * OSI functional model * Assessment, open questions *6 Internet management Internet Activities Board * Internet management architecture model * Internet information model * Simple network management protocol * Internet MIBs * SNMPv2 * Comparison of ISO and IAB approaches to management *7 Other manufacturer-independent architectures IEEE LAN/MAN management * ITU-S telecommunications management network (TMN) * OSF distributed management environment (DME) * ISO open distributed processing (ODP) * Other manufacturer-independent activities *8Gateways between management architectures Protocol gateways * Interface gateways * MIB gateways *9Manufacturer-specific network management architectures and approaches to the migration to open architectures SNA network management * TRANSVIEW (Siemans Nixdorf) * Other manufacturer approaches Part III: Management Tools *10 Properties and classes of tools Introduction * Criteria for classifying management tools * A general classification scheme *11 Isolated management tools Test sets * Protocol analysers * Tools from the internet area * Documentation systems * Trouble ticket systems *12 Management platforms Archetecture of management platforms * Infrastructure of a management platform * User interface * Basic applications * Selection criteria *13 Development tools for management MIB tools * Tools for designing user interfaces * Development environments for implementing management applications *14 Integration of management tools into platforms Forms of integration * User-interface integration * Integration via a proxy agent * Data integration * Total integration Part IV: Tried and Tested Management Scenarios *15 Component management Introduction to the management scenario * Management of LAN components * Management of WAN components *16 System management Management areas from the user's viewpoint * Management areas from the administrator's viewpoint * Integration of system management Part V: Future Management Scenarios, Open Questions *17 Application management Introduction to the management scenario * ODP as the basis for integrated application management * Existing solutions *18 Enterprise management Introduction to the management scenario * Positioning the management problem in the enterprise context * Technical possibilities for implementing corporate management * View of an enterprise management architecture *19 Open questions in network and system management Information model * Organizational model * Functional model * Integration of system management * Abbreviations * Bibliography * Index

Integrated network and system management

IT service providers use applications to support their business processes. The need for specialized IT management functionality and information generates a multitude and diversity of management applications that can be recognized in one IT provider's scenario. To run IT and to provide IT services effectively and efficiently, management applications have to be integrated along operational processes. This article introduces an approach to integrate management applications by leveraging a service-oriented architecture (SOA). Therefore, a sufficient understanding of IT service provider's processes and cooperative roles is essential. The presented SOA defines how to integrate management applications loosely coupled in a process-oriented manner, bridging the gap between operational processes and management applications.

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Sebastian Abeck

Papers

Integrated Management of Networked Systems: Concepts, Architectures and their Operational Application

Development of SOA-Based Software Systems - an Evolutionary Programming Approach

An Access Control Metamodel for Web Service-Oriented Architecture

Integrated network and system management

SOA-based integration of IT service management applications