Requirement Capture, Formal Description and Veriication of an Invoicing System Requirement Capture, Formal Description and Veriication of an Invoicing System

The Invoicing case study is a typical business system proposed by Henri Habrias as a common example for a contest on the capacity of particular formal methods to capture requirements from the client. For this, the case study is informally described by half a page of English text. In this report, we use the formal description technique Lotos for requirement capture, formal description and veriication of the Invoicing case study. First, we analyse and interpret the informal requirements of the case study using the Lotos approach for description of systems. This leads to a set of twenty questions about the informal description. By answering to these questions, we obtain a high-level speciication architecture that can be formalised. Then, we present the formal description of the case study in Lotos and, for comparison, in E-Lotos, the new version of Lotos currently being standardized. Since Lotos allows a balance to be struck between process-oriented and data-oriented modeling, descriptions in both styles are given. After that, we verify the Lotos descriptions by model-checking using the Cadp (CCsar/Alddbaran) toolbox. The underlying Labelled Transition System (Lts) models corresponding to various scenarios are generated using the CCsar compiler. We push further the analysis of the case study by formalizing in temporal logic six properties of the system. We verify these properties on the Lts models using the Xtl model-checker. Finally, we study the equivalence of the process-oriented and data-oriented descriptions using the Alddbaran tool. Inggnierie des besoins, description formelle et vriication d'un systtme de facturation RRsumm : L''tude de cas Facturationn est un systtme de gestion classique proposs par Henri Habrias comme un exemple commun pour un ddbat comparatif sur la capacitt des diiirentes mmthodes formelles analyser les besoins des clients. Pour cette raison, le systtme est ddcrit d'une faaon informelle, dans une demi-page de texte en anglais. Dans ce rapport, nous utilisons la technique de description for-melle Lotos pour l'inggnierie des besoins, la description formelle et la vriication de cette tude de cas. Premiirement, nous analysons et nous interprrtons la description informelle des besoins en utili-sant l'approche proposse par Lotos pour la description des systtmes. Ceci nous conduit poser vingt questions sur la description informelle. En rrpondant ces questions, nous obtenons une spciication de haut niveau qui peut tre formalisse. Ensuite, nous prrsentons la description formelle du systtme en Lotos et, pour comparaison, en E-Lotos, la nouvelle version de Lotos en cours de normalisa-tion. Puisque …