Platform as a service (PAAS) featuring computer software platforms for providing isolated virtual test and debugging environments for the execution of automated software testing and build processes, hosted on the same computing infrastructure as providers' continuous integration and continuous deployment (CI/CD) runner infrastructure; platform as a service (PAAS) featuring computer software platforms for provisioning and managing virtual machine-based computing environments for software testing and continuous integration; platform as a service (PAAS) featuring computer software platforms for synchronizing source code and running automated software builds and tests in remote virtual environments