added missing test docstring
added missing test docstring


Former-commit-id: 30991c5ea2688469648c38afce13ccd46c65ca56 [formerly f2f81f12845441e85fd2862864e1b47fd80f2d5f]
Former-commit-id: 1e2098e2dff6a09ce73b8562c86d45c87be67268
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine