Correctness Of Model Transformations Research Articles

Model Transformation Testing and Debugging: A Survey

Model transformations are the key technique in Model-Driven Engineering (MDE) to manipulate and construct models. As a consequence, the correctness of software systems built with MDE approaches relies mainly on the correctness of model transformations, and thus, detecting and locating bugs in model transformations have been popular research topics in recent years. This surge of work has led to a vast literature on model transformation testing and debugging, which makes it challenging to gain a comprehensive view of the current state-of-the-art. This is an obstacle for newcomers to this topic and MDE practitioners to apply these approaches. This article presents a survey on testing and debugging model transformations based on the analysis of 140 papers on the topics. We explore the trends, advances, and evolution over the years, bringing together previously disparate streams of work and providing a comprehensive view of these thriving areas. In addition, we present a conceptual framework to understand and categorize the different proposals. Finally, we identify several open research challenges and propose specific action points for the model transformation community.

Automatic verification of behavior preservation at the transformation level for relational model transformation

The correctness of model transformations is a crucial element for model-driven engineering of high-quality software. In particular, behavior preservation is an important correctness property avoiding the introduction of semantic errors during the model-driven engineering process. Behavior preservation verification techniques show some kind of behavioral equivalence or refinement between source and target model of the transformation. Automatic tool support is available for verifying behavior preservation at the instance level, i.e., for a given source and target model specified by the model transformation. However, until now there is no sound and automatic verification approach available at the transformation level, i.e., for all source and target models. In this article, we extend our results presented in earlier work (Giese and Lambers, in: Ehrig et al (eds) Graph transformations, Springer, Berlin, 2012) and outline a new transformation-level approach for the sound and automatic verification of behavior preservation captured by bisimulation resp. simulation for outplace model transformations specified by triple graph grammars and semantic definitions given by graph transformation rules. In particular, we first show how behavior preservation can be modeled in a symbolic manner at the transformation level and then describe that transformation-level verification of behavior preservation can be reduced to invariant checking of suitable conditions for graph transformations. We demonstrate that the resulting checking problem can be addressed by our own invariant checker for an example of a transformation between sequence charts and communicating automata.

Spectrum-Based Fault Localization in Model Transformations

Model transformations play a cornerstone role in Model-Driven Engineering (MDE), as they provide the essential mechanisms for manipulating and transforming models. The correctness of software built using MDE techniques greatly relies on the correctness of model transformations. However, it is challenging and error prone to debug them, and the situation gets more critical as the size and complexity of model transformations grow, where manual debugging is no longer possible. Spectrum-Based Fault Localization (SBFL) uses the results of test cases and their corresponding code coverage information to estimate the likelihood of each program component (e.g., statements) of being faulty. In this article we present an approach to apply SBFL for locating the faulty rules in model transformations. We evaluate the feasibility and accuracy of the approach by comparing the effectiveness of 18 different state-of-the-art SBFL techniques at locating faults in model transformations. Evaluation results revealed that the best techniques, namely Kulcynski2 , Mountford , Ochiai , and Zoltar , lead the debugger to inspect a maximum of three rules to locate the bug in around 74% of the cases. Furthermore, we compare our approach with a static approach for fault localization in model transformations, observing a clear superiority of the proposed SBFL-based method.

A feedback technique for unsatisfiable UML/OCL class diagrams

SUMMARYIn Model‐Driven Development (MDD), detection of model defects is necessary for correct model transformations. Formal verification tools and techniques can to some extent verify models. However, scalability is a serious issue in relation to verification of complex UML/OCL class diagrams. We have proposed a model slicing technique that slices the original model into submodels to address the scalability issue. A submodel can be detected as unsatisfiable if there are no valid values for one or more attributes of an object in the diagram or if the submodel provides inconsistent conditions on the number of objects of a given type. In this paper, we propose a novel feedback technique through model slicing that detects unsatisfiable submodels and their integrity constraints among the complex hierarchy of an entire UML/OCL class diagram. The software developers can therefore focus their revision efforts on the incorrect submodels while ignoring the rest of the model. Copyright © 2013 John Wiley & Sons, Ltd.

Formal Description for Component-based Architecture Model Transformation

As semantic consistency becomes the most important criterion of the correctness of model transformations in model-driven software development, the definition, description, and proof of semantic property preservation become crucial. This paper extends typed category theory to provide a formal description approach for architecture model transformation. Category diagrams are used to provide formal semantics of component specifications and architecture models. The transformation between different levels of models is formally described by morphisms. The approach can be used for the description, analysis and judgment of property preservation to strengthen the understandability and traceability of model transformations. The application research shows that the approach captures the essence, process and requirements of model transformation, and thus can make an effective support for model-driven software development.

Correct-by-construction synthesis of model transformations using transformation patterns

Model transformations are an essential part of model-based development approaches, such as Model-driven Architecture (MDA) and Model-driven Development (MDD). Model transformations are used to refine and abstract models, to re-express models in a new modelling language, and to analyse, refactor, compare and improve models. Therefore, the correctness of model transformations is critically important for successful application of model-based development: software developers should be able to rely upon the correct processing of their models by transformations in the same way that they rely upon compilers to produce correct executable versions of their programs. In this paper, we address this problem by defining standard structures for model transformation specifications and implementations, which serve as patterns and strategies for constructing a wide range of model transformations. These are incorporated into a tool-supported process which automatically synthesises implementations of model transformations from their specifications, these implementations are correct-by-construction with respect to their specifications.

Bridging the gap between formal semantics and implementation of triple graph grammars

The correctness of model transformations is a crucial element for model-driven engineering of high-quality software. A prerequisite to verify model transformations at the level of the model transformation specification is that an unambiguous formal semantics exists and that the implementation of the model transformation language adheres to this semantics. However, for existing relational model transformation approaches, it is usually not really clear under which constraints particular implementations really conform to the formal semantics. In this paper, we will bridge this gap for the formal semantics of triple graph grammars (TGG) and an existing efficient implementation. While the formal semantics assumes backtracking and ignores non-determinism, practical implementations do not support backtracking, require rule sets that ensure determinism, and include further optimizations. Therefore, we capture how the considered TGG implementation realizes the transformation by means of operational rules, define required criteria, and show conformance to the formal semantics if these criteria are fulfilled. We further outline how static and runtime checks can be employed to guarantee these criteria.

A Typed Attributed Graph Grammar with Inheritance for the Abstract Syntax of UML Class and Sequence Diagrams

According to the UML Standard 2.0 class and sequence diagrams are defined in a descriptive way by a MOF meta-model and semi-formal constraints. This paper presents a formal and constructive definition of the abstract syntax of UML class and sequence diagrams based on the well-defined theory of typed attributed graph transformation with inheritance and application conditions. The generated language covers all important features of these parts of UML diagrams and is shown to satisfy all of the corresponding constraints by construction. An explicit model transformation demonstrates the close correspondence between the graph grammar and the MOF definition of UML class and sequence diagrams. The graph grammar is validated by well-established benchmarks showing that all important features of the MOF definition of UML are covered. This formal constructive syntax definition of UML class and sequence diagrams is the basis for syntax directed editing, formal analysis, formal operational and denotational semantics and correctness of model transformations.

Ensuring Containment Constraints in Graph-based Model Transformation Approaches

Within model driven software development, model transformation has become a key activity. A number of transformation approaches for metamodel-defined modeling languages have been developed in the past years and are going to be established in research and industry. None of these have made it to a standard yet. There is a demand for correct model transformation in various senses. Formal methods are helpful for showing correctness issues of model transformations. As one approach, graph transformation has been applied to the field of model transformation and is a perspective for achieving provable correct model transformations. We show in this paper, that containment associations as proposed by the OMG are an integral part of MOF-based languages and imply a couple of constraints which must be ensured in model transformation approaches. Based on a double-pushout approach to graph transformation, conditions are stated that ensure these containment constraints. This is an important step for achieving formal transformation semantics for modeling languages based on MOF, or specifically EMF.

VPM: A visual, precise and multilevel metamodeling framework for describing mathematical domains and UML (The Mathematics of Metamodeling is Metamodeling Mathematics)

As UML 2.0 is evolving into a family of languages with individually specified semantics, there is an increasing need for automated and provenly correct model transformations that (i) assure the integration of local views (different diagrams) of the system into a consistent global view, and, (ii) provide a well-founded mapping from UML models to different semantic domains (Petri nets, Kripke automaton, process algebras, etc.) for formal analysis purposes as foreseen, for instance, in submissions for the OMG RFP for Schedulability, Performance and Time. However, such transformations into different semantic domains typically require the deep understanding of the underlying mathematics, which hinders the use of formal specification techniques in industrial applications. In the paper, we propose a multilevel metamodeling technique with precise static and dynamic semantics (based on a refinement calculus and graph transformation) where the structure and operational semantics of mathematical models can be defined in a UML notation without cumbersome mathematical formulae.