Browsing by Author "Degutis, Daniel Ryan"

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Open Access
How to speed up BDD automated acceptance testing for safety-critical systems
(2018) Degutis, Daniel Ryan
An important aspect of developing safety-critical systems is testing, and in some cases an agile development and testing approach is desirable. To reflect and test safety requirements, a process based on Behavior Driven Development (BDD) is considered in this work. The goal is to have an as efficient as possible process for BDD automated acceptance testing. The original process for this, used in an earlier experiment, is examined and automatable parts are identified. Based on this, improvements to the process are proposed and implemented. This results in an updated process, that utilizes a newly implemented command line tool written for the purpose of producing test cases. These can then be used for the BDD automated acceptance testing process. Finally, an evaluation with students BDD acceptance testing a sample system is conducted, to determine the effectiveness of the improved process. The results of the evaluation show benefits in productivity when using the improved process.
Open Access
Modeling and transformation of serverless workflows
(2020) Degutis, Daniel Ryan
The serverless computing paradigm focuses on development of cloud applications, which do not require management of underlying infrastructure. Instead cloud providers are responsible for all management tasks such as provisioning, resource allocation and scaling. Function-as-a-Service (FaaS) is a cloud service model which makes use of the serverless computing concept. FaaS platforms allow hosting user-provided and typically stateless functions, which can be invoked in an event-driven manner. Cloud applications can make use of such serverless functions by composing them into larger, more complex workflows. For this purpose, the various cloud providers offer their own proprietary serverless function orchestrators. These orchestrators have different formats and approaches. Some orchestrators express workflows declaratively while others make use of existing programming languages and utilize imperative control flow constructs. Consequently, the orchestrators have different capabilities and limitations, which results in a portability issue. If a serverless workflow should be modeled for more than one platform, it would require defining it multiple times using provider-specific formats. Also, some functionalities might only be available in some orchestrators. In this work it is analyzed which existing concepts can be used to enable uniform modeling of serverless workflows and how resulting generic workflow models can be transformed into provider-specific orchestrators. Furthermore, the challenges and pitfalls of the introduced approach are discussed. To validate the approach, a prototype which enables uniform modeling of serverless workflows for three major public cloud providers is implemented. Finally, in a case study, the prototype is used with a sample workflow, to generate orchestrator-specific workflow definitions for all supported orchestrators.