I think Levi Osborne's approach is probably your best option, but read on ...
In the past we (the University of Canterbury) have been reluctant to offer a free Jobe service because of the steadily growing use of CodeRunner and associated costs in supporting and managing such a service. However, we might be prepared to support low-volume users such as yourself if:
- You appreciate that there are no guarantees of quality of service.
- You appreciate that the service might cease in the future.
- You will accept that the service is limited to a certain maximum number of submissions per hour. If that limited is exceeded, further submissions will generate an error message until the start of the next hour.
- You undertake to ensure that the version 3.7.6 or later of CodeRunner is installed on your Moodle server as soon as it becomes available. This will display a small-font message like "Run on University of Canterbury's Jobe server." below the result table on all runs.
I am not sure what number might be appropriate for (3) above and would be interested to hear from you what you think you might want. Note that running CodeRunner-based tests and exams is unlikely to be feasible with any such limit, even with classes as small as 20 students.
If you are interested in pursuing this option, please email me (email@example.com) directly, including a value for (3) above that you think might be sufficient for your needs. I will then discuss with our IT staff whether we can accommodate your needs. If so we will give you your own personal API key on our jobe2 service, which will be throttled to the submission rate you nominate.