Automatic Testing Approaches For Serverless Applications In AWS

With the increasing popularity of cloud services and cloud-native applications, serverless functions (FaaS, or Function-as-a-Service) are an emerging pattern for cloud application development. While the topic is under active research, little is known about how practitioners can apply existing automatic testing practices to serverless functions. Current research note that the tight coupling with cloud services, lack of tools, and reduced monitoring and observability capabilities introduce challenges to testing and troubleshooting serverless functions. This thesis aims to identify and document practical automatic testing approaches for serverless functions built for the Amazon Web Services cloud platform. The thesis discusses the fundamental concepts of serverless functions and software testing, the current state of the technology, and collects possible testing approaches by conducting a literature review of guidebooks. The testing approaches are applied in practice to a full-stack application, where the back end application comprises a serverless function and a cloud database service. Unit, integration, and system testing approaches are examined and applied to the application. The study identifies three distinct integration testing approaches; local, hybrid, and cloud integration testing. Each of the approaches varies based on the level of mocking used and the utilization of real-world cloud services. The study showcases how to test serverless functions using current tools, including an Infrastructure-as-Code framework, and discusses the advantages and disadvantages involved with each testing approach