add tests for Collection metadata
add tests for Collection metadata

Kitware/girder,jbeezley/girder,girder/girder,manthey/girder,Kitware/girder,Kitware/girder,jbeezley/girder,jbeezley/girder,RafaelPalomar/girder,Kitware/girder,RafaelPalomar/girder,RafaelPalomar/girder,manthey/girder,manthey/girder,jbeezley/girder,girder/girder,manthey/girder,girder/girder,girder/girder,RafaelPalomar/girder,RafaelPalomar/girder