Add test for snapshot
Add test for snapshot

Gouthamve/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,kangwoo/prometheus,prometheus/prometheus,alileza/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,Gouthamve/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,alileza/prometheus,prometheus/prometheus,keegancsmith/prometheus,kangwoo/prometheus,prometheus/prometheus,Gouthamve/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,prometheus/tsdb,GoogleCloudPlatform/prometheus,Gouthamve/tsdb,alileza/prometheus,prometheus/prometheus