extend JobManager TestCase

I added a testcase to the JobManagerTest to test the deferring because of missing requirements (I had problems with the JobManager in #2031). It currently fails.

~~If I didn't misunderstood the JobManager logic, it could be fixed by removing the `return JobResult.DEFERRED;` in the JobConsumer file.~~
It doesn't affect the running of the jobs, but in case you want to use `getRunIteration()` from inside the job it doesn't give you a correct value at the moment.