Abstract: With the fast advancements in cloud computing and
software- as-a-service (SaaS), testing and evaluation of cloud-
based software and SaaS applications became an important task for
engineers. Since most existing tools are not developed to support
cloud-based software testing and SaaS evaluation, there is a strong
demand for a new cloud-based testing infrastructure and evaluation
environment for SaaS applications. This paper proposes a testing-
as-service (TaaS) infrastructure and reports a cloud-based TaaS
environment with tools (known as CTaaS) developed to meet the
needs in SaaS testing, performance and scalability evaluation. The
paper presents TaaS concepts and CTaaS, including their
infrastructure, design and implementation. In addition, the paper
demonstrates the application results of our previously proposed
graphic models and metrics for SaaS performance and scalability
evaluation. Moreover, the paper reports one case study for a
selected SaaS (OrangeHRM) using the developed TaaS
environment.