added first unit test for SessionCache.get()
added first unit test for SessionCache.get()


Former-commit-id: 63b18ccae5db8775cfa089c9cf948c03530a35d3 [formerly f714a14652813a50efff82111e126e466a7f55de] [formerly f714a14652813a50efff82111e126e466a7f55de [formerly 7cdcb703d3078b74218b9dc33fe1e25f8ac2b108]]
Former-commit-id: 58b9f320c7cf5f56ea49268c2195a0ab1f2e265c
Former-commit-id: d3ea9110395b850bb3ae8af92683426bce1005ef
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine