Desenvolvimento, testes e qualidade de software

RESUMO: Hoje em dia o software tornou-se num elemento útil na vida das pessoas e das empresas. Existe cada vez mais a necessidade de utilização de aplicações de qualidade, com o objectivo das empresas se diferenciarem no mercado. As empresas produtoras de software procuram aumentar a qualidade nos seus processos de desenvolvimento, com o objectivo de garantir a qualidade do produto final. A dimensão e complexidade do software aumentam a probabilidade do aparecimento de não-conformidades nestes produtos, resultando daí o interesse pela actividade de testes de software ao longo de todo o seu processo de concepção, desenvolvimento e manutenção. Muitos projectos de desenvolvimento de software são entregues com atraso por se verificar que na data prevista para a sua conclusão não têm um desempenho satisfatório ou por não serem confiáveis, ou ainda por serem difíceis de manter. Um bom planeamento das actividades de produção de software significa usualmente um aumento da eficiência de todo o processo produtivo, pois poderá diminuir a quantidade de defeitos e os custos que decorrem da sua correcção, aumentando a confiança na utilização do software e a facilidade da sua operação e manutenção. Assim se reconhece a importância da adopção de boas práticas no desenvolvimento do software. Para isso deve-se utilizar uma abordagem sistemática e organizada com o intuito de produzir software de qualidade. Esta tese descreve os principais modelos de desenvolvimento de software, a importância da engenharia dos requisitos, os processos de testes e principais validações da qualidade de software e como algumas empresas utilizam estes princípios no seu dia-a-dia, com o intuito de produzir um produto final mais fiável. Descreve ainda alguns exemplos como complemento ao contexto da tese. ABSTRACT: Nowadays the software has become a useful element in people's lives and it is increasingly a need for the use of quality applications from companies in order to differentiate in the market. The producers of software increase quality in their development processes, in order to ensuring final product quality. The complexity and size of software, increases the probability of the emergence of non-conformities in these products, this reason increases of interest in the business of testing software throughout the process design, development and maintenance. Many software development projects are postpone because in the date for delivered it’s has not performed satisfactorily, not to be trusted, or because it’s harder to maintain. A good planning of software production activities, usually means an increase in the efficiency of all production process, because it can decrease the number of defects and the costs of it’s correction, increasing the reliability of software in use, and make it easy to operate and maintenance. In this manner, it’s recognized the importance of adopting best practices in software development. To produce quality software, a systematic and organized approach must be used. This thesis describes the main models of software development, the importance of requirements engineering, testing processes and key validation of software quality and how some companies use these principles daily, in order to produce a final product more reliable. It also describes some examples in addition to the context of this thesis.

Verificación Formal de Sistemas basada Formal Software Verification based on Automated Analysisen Análisis Automático.

Identificación y caracterización del problema. Uno de los problemas más importantes asociados con la construcción de software es la corrección del mismo. En busca de proveer garantías del correcto funcionamiento del software, han surgido una variedad de técnicas de desarrollo con sólidas bases matemáticas y lógicas conocidas como métodos formales. Debido a su naturaleza, la aplicación de métodos formales requiere gran experiencia y conocimientos, sobre todo en lo concerniente a matemáticas y lógica, por lo cual su aplicación resulta costosa en la práctica. Esto ha provocado que su principal aplicación se limite a sistemas críticos, es decir, sistemas cuyo mal funcionamiento puede causar daños de magnitud, aunque los beneficios que sus técnicas proveen son relevantes a todo tipo de software. Poder trasladar los beneficios de los métodos formales a contextos de desarrollo de software más amplios que los sistemas críticos tendría un alto impacto en la productividad en tales contextos. Hipótesis. Contar con herramientas de análisis automático es un elemento de gran importancia. Ejemplos de esto son varias herramientas potentes de análisis basadas en métodos formales, cuya aplicación apunta directamente a código fuente. En la amplia mayoría de estas herramientas, la brecha entre las nociones a las cuales están acostumbrados los desarrolladores y aquellas necesarias para la aplicación de estas herramientas de análisis formal sigue siendo demasiado amplia. Muchas herramientas utilizan lenguajes de aserciones que escapan a los conocimientos y las costumbres usuales de los desarrolladores. Además, en muchos casos la salida brindada por la herramienta de análisis requiere cierto manejo del método formal subyacente. Este problema puede aliviarse mediante la producción de herramientas adecuadas. Otro problema intrínseco a las técnicas automáticas de análisis es cómo se comportan las mismas a medida que el tamaño y complejidad de los elementos a analizar crece (escalabilidad). Esta limitación es ampliamente conocida y es considerada crítica en la aplicabilidad de métodos formales de análisis en la práctica. Una forma de atacar este problema es el aprovechamiento de información y características de dominios específicos de aplicación. Planteo de objetivos. Este proyecto apunta a la construcción de herramientas de análisis formal para contribuir a la calidad, en cuanto a su corrección funcional, de especificaciones, modelos o código, en el contexto del desarrollo de software. Más precisamente, se busca, por un lado, identificar ambientes específicos en los cuales ciertas técnicas de análisis automático, como el análisis basado en SMT o SAT solving, o el model checking, puedan llevarse a niveles de escalabilidad superiores a los conocidos para estas técnicas en ámbitos generales. Se intentará implementar las adaptaciones a las técnicas elegidas en herramientas que permitan su uso a desarrolladores familiarizados con el contexto de aplicación, pero no necesariamente conocedores de los métodos o técnicas subyacentes. Materiales y métodos a utilizar. Los materiales a emplear serán bibliografía relevante al área y equipamiento informático. Métodos. Se emplearán los métodos propios de la matemática discreta, la lógica y la ingeniería de software. Resultados esperados. Uno de los resultados esperados del proyecto es la individualización de ámbitos específicos de aplicación de métodos formales de análisis. Se espera que como resultado del desarrollo del proyecto surjan herramientas de análisis cuyo nivel de usabilidad sea adecuado para su aplicación por parte de desarrolladores sin formación específica en los métodos formales utilizados. Importancia del proyecto. El principal impacto de este proyecto será la contribución a la aplicación práctica de técnicas formales de análisis en diferentes etapas del desarrollo de software, con la finalidad de incrementar su calidad y confiabilidad. A crucial factor for software quality is correcteness. Traditionally, formal approaches to software development concentrate on functional correctness, and tackle this problem basically by being based on well defined notations founded on solid mathematical grounds. This makes formal methods better suited for analysis, due to their precise semantics, but they are usually more complex, and require familiarity and experience with the manipulation of mathematical definitions. So, their acceptance by software engineers is rather restricted, and formal methods applications have been confined to critical systems. Nevertheless, it is obvious that the advantages that formal methods provide apply to any kind of software system. It is accepted that appropriate software tool support for formal analysis is essential, if one seeks providing support for software development based on formal methods. Indeed, some of the relatively recent sucesses of formal methods are accompanied by good quality tools that automate powerful analysis mechanisms, and are even integrated in widely used development environments. Still, most of these tools either concentrate on code analysis, and in many cases are still far from being simple enough to be employed by software engineers without experience in formal methods. Another important problem for the adoption of tool support for formal methods is scalability. Automated software analysis is intrinsically complex, and thus techniques do not scale well in the general case. In this project, we will attempt to identify particular modelling, design, specification or coding activities in software development processes where to apply automated formal analysis techniques. By focusing in very specific application domains, we expect to find characteristics that might be exploited to increase the scalability of the corresponding analyses, compared to the general case.

Aplicación de la ingeniería software sobre la herramienta MATE Analyzer

MATE (Monitoring, Analysis and Tuning Environment) es un proyecto que surge en 2004 como tesis doctoral de Anna Sikora con el propósito de investigar la mejora de rendimiento de aplicaciones paralelas a través de la modificación dinámica. Nuestro proyecto supone un paso adelante en cuestiones de calidad de software y pretende dotar al proyecto MATE de una base de desarrollo sólida de cara a futuras lineas de trabajo. Para ello se hace frente a la problemática desde tres perspectivas: la creación de una metodología de desarrollo (y su aplicación sobre el proyecto existente), la implantación de un entorno de desarrollo de soporte y el desarrollo de nuevas características para favorecer la portabilidad y la usabilidad, entre otros aspectos.

Estudi de diferents estàndards de qualitat al voltant de les activitats d'un departament de sistemes d'informació

Aquest estudi aborda la qualitat del programari i analitza una selecció d'estàndards significatius per la millora dels processos que donen suport a l'enginyeria del programari. Posteriorment es presenten uns criteris de categorització per finalment proposar una classificació dels estàndards de qualitat analitzats.

Improving globally distributed software development and support processes - A workflow view

We propose a new approach and related indicators for globally distributed software support and development based on a 3-year process improvement project in a globally distributed engineering company. The company develops, delivers and supports a complex software system with tailored hardware components and unique end-customer installations. By applying the domain knowledge from operations management on lead time reduction and its multiple benefits to process performance, the workflows of globally distributed software development and multitier support processes were measured and monitored throughout the company. The results show that the global end-to-end process visibility and centrally managed reporting at all levels of the organization catalyzed a change process toward significantly better performance. Due to the new performance indicators based on lead times and their variation with fixed control procedures, the case company was able to report faster bug-fixing cycle times, improved response times and generally better customer satisfaction in its global operations. In all, lead times to implement new features and to respond to customer issues and requests were reduced by 50%.

Classification-Based compression of Multispectral Images

The purpose of this thesis is to present a new approach to the lossy compression of multispectral images. Proposed algorithm is based on combination of quantization and clustering. Clustering was investigated for compression of the spatial dimension and the vector quantization was applied for spectral dimension compression. Presenting algo¬rithms proposes to compress multispectral images in two stages. During the first stage we define the classes' etalons, another words to each uniform areas are located inside the image the number of class is given. And if there are the pixels are not yet assigned to some of the clusters then it doing during the second; pass and assign to the closest eta¬lons. Finally a compressed image is represented with a flat index image pointing to a codebook with etalons. The decompression stage is instant too. The proposed method described in this paper has been tested on different satellite multispectral images from different resources. The numerical results and illustrative examples of the method are represented too.

Software process improvement using an electronic process guide

Kasvava kiinnostus ohjelmistojen laatua kohtaan on herättänyt ohjelmistoprosesseihin ja niiden kehittämiseen kohdistuvaa huomiota viime vuosina. Ohjelmistoyritykset ympäri maailmaa ovat ottaneet käyttöön ohjelmistoprosessin kehittämismalleja, kuten CMM ja SPICE, pyrkiessään kohti parempilaatuisia ohjelmistotuotteita. Samalla on huomattu, että tehokas prosessien parantaminen ja suorittaminen tarvitsee tuekseen kuvauksen prosessista, jotta prosessin perusteellinen ymmärtäminen ja kommunikointi olisi mahdollista. Ohjelmistoprosesseja voidaan kuvata monilla eri tavoilla. Prosessiopas on prosessin esitysmuoto, jonka päätarkoituksena on helpottaa prosessin ymmärtämistä ja kommunikointia. Elektroninen prosessiopas on Web-teknologiaa hyödyntävä prosessiopas. Tässä työssä luodaan kehitysympäristö elektronisille prosessioppaille, joiden tarkoituksena on tukea ohjelmistoprosessin kehittämistä ja suorittamista. Ympäristö mahdollistaa ohjelmistoprosessinmallintamisen sekä yksilöllisten oppaiden luomisen ja muokkaamisen. Kehitysympäristöä käytetään mallintamaan tietoliikenneohjelmistoja valmistavan yrityksen ohjelmistoprosessia sekä luomaan elektronisia prosessioppaita tukemaan prosessin kehitystä ja suorittamista. Lopuksi pohditaan prosessioppaiden tarjoamaa tukea sekä mahdollisuuksia kohdeyrityksessä.

A proposal for a repertoire of software testing methods

Nowadays software testing and quality assurance have a great value in software development process. Software testing does not mean a concrete discipline, it is the process of validation and verification that starts from the idea of future product and finishes at the end of product’s maintenance. The importance of software testing methods and tools that can be applied on different testing phases is highly stressed in industry. The initial objectives for this thesis were to provide a sufficient literature review on different testing phases and for each of the phases define the method that can be effectively used for improving software’s quality. Software testing phases, chosen for study are: unit testing, integration testing, functional testing, system testing, acceptance testing and usability testing. The research showed that there are many software testing methods that can be applied at different phases and in the most of the cases the choice of the method should be done depending on software type and its specification. In the thesis the problem, concerned to each of the phases was identified; the method that can help in eliminating this problem was suggested and particularly described.

Geostatistics and remote sensing methods in the classification of images of areas cultivated with citrus

This study compares the precision of three image classification methods, two of remote sensing and one of geostatistics applied to areas cultivated with citrus. The 5,296.52ha area of study is located in the city of Araraquara - central region of the state of São Paulo (SP), Brazil. The multispectral image from the CCD/CBERS-2B satellite was acquired in 2009 and processed through the Geographic Information System (GIS) SPRING. Three classification methods were used, one unsupervised (Cluster), and two supervised (Indicator Kriging/IK and Maximum Likelihood/Maxver), in addition to the screen classification taken as field checking.. Reliability of classifications was evaluated by Kappa index. In accordance with the Kappa index, the Indicator kriging method obtained the highest degree of reliability for bands 2 and 4. Moreover the Cluster method applied to band 2 (green) was the best quality classification between all the methods. Indicator Kriging was the classifier that presented the citrus total area closest to the field check estimated by -3.01%, whereas Maxver overestimated the total citrus area by 42.94%.

Intended Quality: Relationships between Development, Testing and Quality

An empirical study was conducted in the area of software engineering to study relationships between development, testing and intended software quality. International standards served as a starting point of the study. For analysis a round of interviews was kept and transcribed. It was found that interaction between humans is critical, especially in transferring knowledge and standards’ processes. The standards are communicated through interaction and learning processes are involved before compliance. One of the results was that testing is the key to sufficient quality. The outcome was that successful interaction, sufficient testing and compliance with the standards combined with good motivation may provide most repeatable intended quality.

Cost-benefit analysis of using test automation in the development of embedded software

The goal of this thesis is to make a case study of test automation’s profitability in the development of embedded software in a real industrial setting. The cost-benefit analysis is done by considering the costs and benefits test automation causes to software development, before the software is released to customers. The potential benefits of test automation regarding software quality after customer release were not estimated. Test automation is a significant investment which often requires dedicated resources. When done accordingly, the investment in test automation can produce major cost savings by reducing the need for manual testing effort, especially if the software is developed with an agile development framework. It can reduce the cost of avoidable rework of software development, as test automation enables the detection of construction time defects in the earliest possible moment. Test automation also has many pitfalls such as test maintainability and testability of the software, and if those areas are neglected, the investment in test automation may become worthless or it may even produce negative results. The results of this thesis suggest that test automation is very profitable at the company under study.

A Mono- and Multi-objective Approach for Recommending Software Refactoring

Les systèmes logiciels sont devenus de plus en plus répondus et importants dans notre société. Ainsi, il y a un besoin constant de logiciels de haute qualité. Pour améliorer la qualité de logiciels, l’une des techniques les plus utilisées est le refactoring qui sert à améliorer la structure d'un programme tout en préservant son comportement externe. Le refactoring promet, s'il est appliqué convenablement, à améliorer la compréhensibilité, la maintenabilité et l'extensibilité du logiciel tout en améliorant la productivité des programmeurs. En général, le refactoring pourra s’appliquer au niveau de spécification, conception ou code. Cette thèse porte sur l'automatisation de processus de recommandation de refactoring, au niveau code, s’appliquant en deux étapes principales: 1) la détection des fragments de code qui devraient être améliorés (e.g., les défauts de conception), et 2) l'identification des solutions de refactoring à appliquer. Pour la première étape, nous traduisons des régularités qui peuvent être trouvés dans des exemples de défauts de conception. Nous utilisons un algorithme génétique pour générer automatiquement des règles de détection à partir des exemples de défauts. Pour la deuxième étape, nous introduisons une approche se basant sur une recherche heuristique. Le processus consiste à trouver la séquence optimale d'opérations de refactoring permettant d'améliorer la qualité du logiciel en minimisant le nombre de défauts tout en priorisant les instances les plus critiques. De plus, nous explorons d'autres objectifs à optimiser: le nombre de changements requis pour appliquer la solution de refactoring, la préservation de la sémantique, et la consistance avec l’historique de changements. Ainsi, réduire le nombre de changements permets de garder autant que possible avec la conception initiale. La préservation de la sémantique assure que le programme restructuré est sémantiquement cohérent. De plus, nous utilisons l'historique de changement pour suggérer de nouveaux refactorings dans des contextes similaires. En outre, nous introduisons une approche multi-objective pour améliorer les attributs de qualité du logiciel (la flexibilité, la maintenabilité, etc.), fixer les « mauvaises » pratiques de conception (défauts de conception), tout en introduisant les « bonnes » pratiques de conception (patrons de conception).

Discriminative pattern mining in software fault detection

We present a method to enhance fault localization for software systems based on a frequent pattern mining algorithm. Our method is based on a large set of test cases for a given set of programs in which faults can be detected. The test executions are recorded as function call trees. Based on test oracles the tests can be classified into successful and failing tests. A frequent pattern mining algorithm is used to identify frequent subtrees in successful and failing test executions. This information is used to rank functions according to their likelihood of containing a fault. The ranking suggests an order in which to examine the functions during fault analysis. We validate our approach experimentally using a subset of Siemens benchmark programs.