Harald Wesenberg

The Impact of Test Driven Development on the Evolution of a Reusable Framework of Components An Industrial Case Study

Test driven development (TDD) is a software engineering technique to promote fast feedback, task-oriented development, improved quality assurance and more comprehensible low-level software design. Benefits have been shown for non-reusable software development in terms of improved quality (e.g. lower defect density). We have carried out an empirical study of a framework of reusable components, to see whether these benefits can be shown for reusable components. The framework is used in building new applications and provides services to these applications during runtime. The three first versions of this framework were developed using traditional test-last development, while for the two latest versions TDD was used. Our results show benefits in terms of reduced mean defect density (35.86%), when using TDD, over two releases. Mean change density was 76.19% lower for TDD than for test-last development. Finally, the change distribution for the TDD approach was 33.3% perfective, 5.6% adaptive and 61.1% preventive.

Agile enterprise software development using domain-driven design and test first

In this paper we present the experience gained and lessons learned when the IT department at Statoil ASA, a large Oil and Gas company in Norway, applied Domain-Driven design techniques in combination with agile software development practices to assess the software architecture of our next generation oil trading and supply chain application. Our hypothesis was that the use of object oriented techniques, domain driven design and a proper object-relational mapping tool would significantly improve the performance and reduce the code base compared with current legacy systems. The legacy system is based on several Oracle databases serving a variety of clients written in Java, Gupta Centura Team Developer and HTML. The databases have a layer of business logic written in PL/SQL offering various system services to the clients. To validate our new object-oriented software architecture, we re-implemented one of the most computationally heavy and data intensive services using Test First and Domain-Driven design techniques. The resulting software was then tested on a set of servers with a representative subset of data from the production environment. We found that using these techniques improved our software architecture with respect to performance as well as code quality when running on top of our Oracle databases. We also tested the switch to an object database from Versant and achieved additional performance gains.

Understanding Model Quality Concerns When Using Process Models in an Industrial Company

Modelling has been used as a general technique in many companies for the last decades. Some already started using modelling in the eighties, trying out the first industrial CASE-tools. Their usage of modelling techniques has evolved over the years, finding new uses, and thus using the modelling techniques for supporting new goals. In our case company semi-formal modelling techniques have been taken into use on a large scale as a backbone for the company’ quality system. In this paper we report on the use of process modelling in particular on the aspects found necessary to emphasise to achieve the right quality of the models in this organisation, and how the understanding of needed quality has evolved as the usage of modelling has evolved. A recent evaluation of the use of models in the company is reported, using the SEQUAL framework as an analytical lens for understanding and assessing the quality of models. Whereas earlier a focus has been on objective quality characteristics, with detailed guidelines for empirical and syntactic quality of models, the later investigations have identified the importance of also supporting the process to achieve and keep higher level quality on the semantic, pragmatic and social level.

Using domain-driven design to evaluate commercial off-the-shelf software

Purchasing a Commercial-Off-The-Shelf (COTS) package solution can be a complex and daunting task. Selecting and evaluating the right candidate is difficult, especially when the solution aims at the heart of company business. The companys competitive edge must be maintained, while at the same time ensuring the intended goals such as reduced costs and better functional coverage. A good Enterprise Architecture should be a prime tool when evaluating several solutions against the companys needs.In this paper we will recount the experience and lessons learned when we evaluated three COTS systems to replace a set of legacy oil trading and operations systems. Based on weaknesses in our Enterprise Architecture, we applied strategic domain-driven design principles to extend our Enterprise Architecture during the evaluation. We found that these techniques enabled us to thoroughly analyse our domain with the domain experts and provide answers based on tacit domain knowledge, without going through the cost and effort of performing a full-scale architectural analysis. At the same time, the tacit domain knowledge became explicit and shared, easing the communication with various stakeholders.

Architectural improvement by use of strategic level domain-driven design

In this paper we present the experience gained and lessons learned when the IT department at Statoil ASA, a large Oil and Gas company in Norway, extended their Enterprise Architecture with strategic level Domain-Driven design techniques and used the extended Enterprise Architecture to improve the software architecture of a large enterprise system.Traditionally, Enterprise Architecture has been prescribed as the key tool to conquer complexity and align IT development with business priorities and strategies, but we found our Enterprise Architecture too coarse to be practical useful at the software level.By extending our Enterprise Architecture with context maps and the process of context mapping valuable insight was gained, insight that enabled better scoping of new projects and architectural improvement of existing software in a controlled way.In addition, use of responsibility layers combined with context maps reduces the perceived complexity of the architecture. Use of other techniques such as distillation and identification of the core domain looks promising at the tactical level of a single project, but its value is more uncertain at the strategic level.The key issue is that large enterprise systems do not have a single core. On the other hand, at the project level, there should always be a core, and the project is best of by knowing its core domain and aim its best resources to work with the core.

Business Process Modeling of a Quality System in a Petroleum Industry Company

(a) Situation faced: The petroleum industry is characterized by increased focus on safety and compliance with regulations, in addition to efficient operations. Earlier quality systems were represented in large binders of textual documents, which made important governing documentation difficult to access and unusable for operational personnel who wished to gain an overview. (b) Action taken: Based on the existing quality system, a new way of structuring and accessing the material was developed as a collection of 2000 process models with navigational support through an intranet solution whose use was mandatory in the workplace. (c) Results achieved: Improved compliance with regulations and reduction in the number of accidents were observed. This improvement is not attributable only to the restructuring and presentation of the quality system through process models, but the process models are a visible sign of the organization’s focus on safety and compliance, and it has made it easier for workers to find relevant regulations and requirements when dangerous work is to be undertaken. (d) Lessons learned: Although good results have been achieved, there is room for improvement in this large-scale example of the use of process models to structure a company’s quality system. Ensuring that all employees can find all the models they need and that the models are kept up to date based on practice are important challenges. In addition, handling the trade-offs among goals for safety, efficiency, and compliance is a challenge. Modeling practices that were regarded favorably at an earlier stage might come to be seen as insufficient for the future needs. Therefore, professional long-term use of models must be conscientiously pursued over time.

The Influence of Syntactic Quality on Pragmatic Quality of Enterprise Process Models

As approaches and tools for process and enterprise modelling are maturing, these techniques are being taken into use on a large scale in an increasing number of organizations. In this paper we report on the use of process modelling in connection to the quality system of Statoil, a large Norwegian oil company, in particular, on the aspects found necessary to be emphasized to achieve the appropriate quality of the models in this organization. Based on the investigation of usage statistics and user feedback on models, we have identified that there are problems in comprehending some of the models. Some of these models has poorer syntactic quality than the average syntactic quality of models of the same size. An experiment with improving syntactic quality on some of these models has given mixed results, and it appears that certain syntactic errors hinder comprehension more than others.